Utility in Due Process can be incredibly impactful to the outcome of your games, and efficient usage of it can easily swing rounds in your favour.

A match in Due Process is split into segments of 3 rounds, a casual match consisting of 2 of these segments, and a ranked match consisting of 4.
At the start of each 3 round segment, your team will be given a set of weapons and utility that you will use to attempt to win as many of these rounds as you can. Typically, it is best practice to evenly spread out your utility usage across these 3 rounds, to ensure you are not gambling too much on any 1 round. The kicker is that you must do this as a team. There is not enough utility for each player on the team to take 2 utility in all 3 rounds, and so coordinating with your team is essential to ensure you are not wasting the limited amount of utility you are given.

For example, attackers get 12 flashbangs in total, and so taking 4 flashbangs per round is the standard thing to do. Defenders get 8 barb wire, taking 3 barb in 2 of the rounds, and 2 barb in 1 is also the standard.
There may be some cases where you feel it would be better to take more or less of a utility in a round, based on your knowledge of the upcoming maps, or for other various reasons. This is fine, as long as you and your team have planned for this.

Now I'll go through each piece of utility in as much detail as I can. You'll see that I will talk on some utility more than others. Not all utility is created equal, some are meant to be niche in their use, whilst others are meant to be versatile or powerful. But all utility has its purpose.

• Flashbangs are primarily used to flush defenders out of certain positions, and to move their aim off of whatever angle they're holding. Flashbangs do not affect Attackers at all, so you should run in with them rather than waiting for them to go off before pushing. Whilst you might think the primary power in flashbangs is their ability to blind opponents, their concussive effect is actually much more impactful. For this reason, landing flashbangs as close to where you think the defender will be is better than attempting to land it in their field of view, as the closer the flashbang is to them the longer it will concuss them.
  Whilst the concussive effect is based on the proximity to the defender, it is partially blocked by objects, and completely blocked by walls and doors.
  
  The most efficient usage of flashbangs is taking map control, a well placed flashbang will either disable a defender or force them to retreat. For this reason, you must use your flashbangs with intention, usually when your team intends to make a push to take control of a room or part of the map. Make sure to coordinate with your team when you will be flashing, either with icons during the planning phase or simply telling your team where you will flash before you breach.
  
  Flashbangs are an extremely oppressive tool for the Attackers, so Defenders should try to position themselves with flashbangs in mind. For example, standing next to a door can allow you to run out of the room and close the door, so that when the flashbang goes off you will not be affected. Defenders should try to figure out ways to make Attackers waste flashbangs, such as forcing attackers to push through barb wire, or throwing a molotov as soon as you hear the flashbang being thrown.
  
  
• Smoke Grenades are an excellent tool for blocking sightlines, especially useful on the longer range tilesets like Factory and Dome, but still very useful on the other tilesets in certain situations. The smoke grenades last 30 seconds and do not extinguish molotov fire. Because of this, attackers must be careful when pushing through smoke as defenders or fire could be hiding in it.
  
  Using map icons will help a lot in landing accurate smoke grenades, as when you claim an icon you will see it displayed, even through walls.
  Many maps have windows or holes that you can throw utility through, especially Factory and Bank, use these to throw smokes safely.
  
  The smoke cloud goes through walls, allowing you to throw a smoke grenade so that the smoke blocks sightlines on the other side of walls. Very useful on the smaller maps like Killhouse and Cstore to block certain powerful angles.
  The smoke cloud also extends a little below the grenade itself, allowing some niche cases where you can throw the smoke on the roof of a building to block sightlines inside.
  
  
• Frag Grenades are a mix between a weapon and a utility. They can kill anyone, attacker or defender, in one blast if the person is standing close to it. This can make them incredibly impactful when thrown into a small room, or from far away as the defenders will have less time to run. That said, frags are blocked by any object, even the bomb.
  
  Frags have another purpose though, one that I would argue is even more important than killing opponents, they are one of the very few pieces of utility that can remove barb wire. As I will explain later, a well placed barb wire can completely halt an Attackers push, and whilst door charges, wall charges or the torch can also be used to remove them, frags are the safest and quickest way to destroy barb wire. Just be sure not to blow up your teammates in the process.
  
  Due to you only getting 2 frags, I recommend bringing frags with the plan to destroy barb wire, and then using them to attempt to kill only if there is not barb wire in your way. Do ensure to actually use the frag before you die, as a frag in the hands of a defender can be disastrous.
  
  
• The Torch can fully open a few entry points, such as fences, barred windows, factory fans or bank vents. And some things, like Cstore shutters or Factory dock shutters, can have sightlines opened.
  
  The torch can also be used to destroy barb wire, but isn't as safe as an explosive due to how close you need to get to the barb. Having a teammate cover you with their gun or the shield makes the torch an extremely viable way of removing barb wire.
  It is especially useful on maps where you expect the defenders to place 2 barbs in your path, as long as you think you can safely torch both barbs.
  
  The torch's ability to destroy frags for only a bit of fuel forces the defenders to place barbs in a way they can't be torched for "free". This means always being able to molotov, peek or wallbang the player torching. Placing barbs on your side of the door instead of through it, not placing them behind hard cover, etc.
  
  Make sure you're careful with your usage of barb destroying utility. If you use too much in one round you may not have any left for later rounds. If you bring a charge, frag and torch all in round 1 of a set and lose it, you're gonna be left with limited options for the next 2 rounds.
  
  
• The DL-12 Shotgun's utility cannot be understated. You can open green doors by shooting the door handle area, allowing you to open these doors without needing to kick. Kicking leaves attackers very vulnerable, so having a shotgun can help a ton on maps with lots of doors, like Killhouse, Cstore and Bank. Teller doors on Cstore can also be opened from either side with a shotgun.
  The defenders' secondary shotgun is also capable of opening green doors, making this an incredibly powerful pickup for the attackers.

• The Shield can completely block all shots in front of you while you hold right click. This can be very useful to gain information or to protect teammates.
  When standing, the shield will not cover your legs, so when blocking shots from defenders ensure you are crouched.
  
  Attackers will typically want to push fast when clearing rooms or areas, to get the best use out of their flashbangs and get in before defenders can rotate or retreat. Due to the shield slowing you down, it might be better to drop it when your team is pushing in so you can be there to help secure kills. If you see a player push in with a shield, you should target their teammates.
  
  The easiest way to get value out of the shield is to defend a teammate torching a barb, or block wallbangs for your team.
  You can also push into a room if you don't see any defenders and possibly save your team from flashing. If you see a defender, you can call to your team to flash them and drop the shield to take the fight with your team.
  You typically want to avoid pushing through barb wire with shield as the main counter to a shield is a molotov. When you get mollied, you can typically drop the shield and run away while taking minimal damage, but if you're stuck in a barb when the molotov lands you're dead.
  Be very careful of where you take a shield to, you want the defenders to be in front of you, not off to the sides. The shield is very vulnerable to being shot from angles to its sides.
  
  There is a trick with the shield called "bunny-hopping" which can be used to cross spaces very quickly while still having the shield completely cover you, you might be familiar with the term from other games and it works similarly here.
  If you jump, let go of sprint and jump again the moment you hit the floor, you will retain the speed you had in the direction you were moving. You can bind jump to your scroll wheel to make this easier to do.
  If you let go of the movement keys also, you can freely rotate your camera in the air without losing speed.
  
  The shield is held to your front-right when not holding right-click. If, while in the air, you move your camera so the shield is pointed towards where you want to be shielded from, and crouch, you can completely cover your body with the shield.
  Bunny hopping allows you to safely and quickly cross to cover, drop the shield and take fights with your teammates from multiple angles, whereas without the shield you would all be coming from the same angle.
  
  The shield is held in hand, rather than having a spot in your inventory. This means you will drop it on the floor if you switch to another utility or weapon, but also means it frees up your inventory space for other utility.
  If you switch to a weapon, it will drop the shield and pull out your weapon quite quickly, this can be used to kill a defender not looking at you, or otherwise unable to shoot you.
  
  
• Night Vision Goggles can be used on maps with a power switch, namely Cstore, Factory and Dome. You only get 4 night vision goggles but the attackers' sniper also has night vision capabilities, so it is possible for all 5 attackers to get some form of night vision.
  If you don't have night vision you can also use your flashlight by pressing F by default.
  
  Going for power off can give you an advantage as attacker, but will typically require securing areas of the map that would otherwise not be necessary to take. If defenders suspect you will go for the power switch, they will make sure to set up flares at important chokepoints, reducing the advantage you gain. For these reasons, it's important to weigh how worthwhile the investment to take power actually is, and there will be matches where night vision doesn't get used at all.
  
  
• Clackers are used to detonate door or wall charges. To do so you must get close to the charge and clack 3 times to blow it up. Be careful not to get too close though, as being within half a tile of the charge, or 2 tiles (for door charge) / 2.5 tiles (for wall charge) in the direction of the charge's explosion, will cause you to take damage and possibly even die. Any barb wire within this area will also get destroyed, allowing for some scenarios where you use a door or wall charge to specifically destroy barb wire. Be careful when planning around this though, as if a door has been kicked down you cannot place a charge on it.
  
  Door Charges, in most cases, will be used on a red entry point, but you can use them on green doors as well. They can also be used on shutters, similarly to the torch, to open sightlines but this won't allow entry.
  
  Wall Charges can be used on any door just like door charges, but can also be placed on shutters or fences to open them fully and allow entry. They can be placed on most interior walls to allow you to open a new path through the map for creative plays. For example, I see this happen on some Bank maps where you can wall charge directly from the button to the vault door, or vice versa.
  These breachable walls will typically have a grey colour over them on the map, whilst walls that can not be breached will have a black colour. There are some cases where black coloured walls can still be breached, usually on Factory or Dome where the walls are very tall.
  The wall charge is held in hand, rather than having a spot in your inventory. This means you will drop it on the floor if you switch to another utility or weapon, but also means it frees up your inventory space for other utility.
  
  You only get 2 clackers, 2 door charges and 1 wall charge for the 3 rounds. For this reason, it is very important to ensure you don't lose the clackers if possible, as while you have 3 charges, you only have 2 clackers. Ideally, you don't want to be forced into going through the free entrance on the 3rd round, in the event you lost the clackers in the first and second rounds, as the defenders will know you have no clackers left and can prepare entirely for this push.
  That said, it is also important to not give the defenders your clackers, if possible, as they can use them to "counter-clack", where they stand near an entry point they expect you to breach, and spam the clacker so that when the attacker places the charge it immediately explodes, killing the attacker. It is common practice to drop the clacker just outside the entry point you breach, this way you can retrieve it if your team wins the round. Placing it outside makes it much harder for the defenders to pick up the clacker as they can only be outside for a limited time due to the UAV.
  
  Don't be afraid to take a frag and/or the torch and go to the free entrance, leaving your clackers for later rounds. If you still have clackers and charges, the defenders can't be certain you will go through the free entrance, and so as long as you can deal with any barb wire placed there, it can be a good entry point on some maps.
  In the case you are going to go through the free entrance in one of the rounds, you can do what's called a "double charge" in one of the other rounds. In this case, you use either 2 door charges or 1 door charge and 1 wall charge to either breach multiple entry points, or breach an interior door or wall to either destroy barb wire or gain a new pathway through the map. That said, charges are a very important resource, so these rounds are quite risky as losing them can be devastating.

• Barb Wire slows the movement of anyone moving through it. The barb wire is, in my opinion, the most essential piece of utility in the entire game, and figuring out how best to place or counter them can be the difference between winning or losing rounds. Attackers can play very quickly if unimpeded, by shotgunning doors and using flashbangs to force defenders to retreat, they can be extremely oppressive. Barb wire is also an excellent way to force attackers to use up some of their utility.
  Whilst molotovs can halt a push, they only last for a very limited amount of time, barb wire however, is there until the attackers destroy it. That said, you must defend your barb wire, a barb wire with no defender holding it is barely an inconvenience for the attackers, but a barb wire with even just 1 defender holding it can become a wall if the attackers are not prepared for it.
  
  Barbs should be placed in a way that forces the attackers to move through it. The most common way to do this is to place it anywhere where a path through the map narrows to the length or width of the barb, as this way the attackers cannot walk around it. These are chokepoints.
  In your head, visualise the paths the attackers are most likely to take through the map towards the bomb when coming from each of the entry points. Take note of each chokepoint along these paths. Unless an entry point is clearly weaker than the others, you will usually want to barb at least 1 chokepoint along each of these paths if possible, and make sure there are no better alternative routes that the attackers can take if a barb is in their way. Sometimes this will mean pulling back from the entry points and playing closer to the bomb, and that's fine. You can even have some defenders take early shots at the attackers and then fall back behind the barb. But typically you will want to play behind your barbs.
  
  In some cases you can choose to hold on to a barb until you know where the attackers are coming from, this way you can choose between multiple spots where you will place the barb wire.
  If one entry point seems much stronger than the others, or if there is another reason for you to believe the attackers will choose a specific entry point, having multiple barb wire along the path from that entry point is ideal. However, keep your barb wire separated. A single frag grenade can take out multiple barb wire if they are placed too close together.
  Barbing the free entrance is fine as long as you can hold it, some free entrances have windows that make this difficult to do, and in these cases it might be best to move the barbs further into the building, to a chokepoint you can hold better.
  
  You should look to hold the barb wire without being visible to any attackers behind the barb wire. This way you will first see the attacker as they are actively pushing through your barb. When placed in a small chokepoint, a defender can hold the barb wire off to the side at a distance, and when the attackers move through the barb wire, the defenders will see their body before the attackers can see them. Because of this the defender can get off a few crucial first shots, and due to how slow the attackers are moving through barb wire, hitting headshots on them is significantly easier. Throwing a molotov on barb wire while an attacker is moving through it is almost always certain death for them.
  When someone moves through barb wire it makes a distinct sound, allowing you to set up for wallbangs, especially useful on Killhouse with its thin walls. Set up with KRs or Ingmars for thin walls, and Nacks, Legroses or the Dawn for very thick walls or multiple thin walls.
  
  As mentioned earlier in the clackers section, barb wire will be destroyed if it is placed within a charge's blast zone.
  Because of this, barbing entrances that require these explosives to breach is not viable, outside some specific cases. For example, if you know the enemy team has used or lost both of their frag grenades and the torch, you could kick the red door and barb it, as they can't place charges on a kicked door. Another example would be a "Flogel" or "late" barb, where you run past the door right after it has been breached, and drop the barb in the doorway before the attackers enter. Fire extinguishers can make this less dangerous.
  
  To get through barb wire, attackers will typically want to destroy it with an explosive or the torch, but failing that they might be able to push through it with some well placed flashes or the shield. Ideally flashes should be saved for when you can actively push the position you flash, so if attackers are forced to use flashes to push through barb wire it is usually beneficial for the defenders.

• Molotovs are a great tool to delay the attackers from pushing for a short time, as an attacker pushing through it will take a lot of damage. This allows defenders time to reposition to better defend against the attackers' push. Make sure to throw the molotov in front of the entry point on your side, rather than in or through the entry point. This ensures that even if the attackers are very quick with their entry, they will still go through the full length of the fire. That said, sometimes attackers can get through the fire without dying, so having a teammate watch the entry point with their gun out is ideal to prevent you from dying to a fast attacker.
  
  Due to how few molotovs you are given, it is very important, during the planning phase, to mark on the map where you intend to use them. When using molotovs at chokepoints where the attackers set up and prepare a push, such as a red door, you could try to be patient with your molotov. Wait for the sound of an attacker throwing a flashbang, then toss your molotov. This way the attackers will either waste their flashbang or push through the molotov, taking significant damage. In some cases this can even split the attackers, where only 1 or 2 attackers push through the molotov while the rest wait outside. This is risky though, and if you're alone you're much better off just throwing the molotov immediately.
  
  Molotovs are also a very powerful counter to the torch. Some barb spots, like the lobby free entrance on Bank, can be very strong but hard to stop from being torched. If a shield and torch push up to a barb to try to safely remove it, throwing a deep molotov on their side of the barb can deal a ton of damage to any attackers there, as they're forced to retreat through the molotov. Forcing them to take damage like this will at least mean the barb isn't destroyed for free, and in the chaos of them retreating in the molotov, you or a teammate could peek the entry and shoot them for more damage.
  
  
• Fire Extinguishers can be placed on the ground, and if shot or destroyed in an explosion, such as an entry point being breached, cause a smoke cloud to appear. This smoke cloud lasts for 8 seconds. During this time it will extinguish any fire. Fire Extinguishers are currently bugged and do not extinguish fire, the fire will be invisible but you will still take damage.
  This smoke cloud can be used similarly to a molotov, allowing you to rotate or retreat. You could even try to place a barb on the entry point while the smoke is covering you.
  
  Fire extinguishers can also be used in the same way on barb wire that you expect the attackers to destroy with a frag grenade. Place the extinguisher off to the side, out of the view of the attackers but close enough that the frag will hit it.
  
  
• Flares are used when you expect the attackers to shut off the power on Cstore, Factory or Dome. By shutting off the power most lights in the building will shut off, and a few emergency lights will turn on. These emergency lights can be shot out so your source of light as a defender is very limited. Attackers not only have night vision goggles but their flashlights are more powerful than the defenders' flashlights, so flares can help a lot in lights out situations.
  There are also some cases where defenders will want to turn off power themselves, like if the attackers take control of the teller room on cstore, turning the power off can prevent them from opening the storefront shutters.
  
  If the attackers can get to a flare they can pick it up and throw it away, so you want to be able to defend them. Placing flares on your side of barb wire can help significantly in this, as it not only makes it much riskier for the attackers to pick up your flare, but also lights up your barb wire to give you full visibility of it.

Hopefully you gained some insight into how to effectively use your utility in that wall of text.
Some utility, like the fire extinguishers, shield and torch, I have not had the opportunity to play with extensively, as they were not yet in the game when I played competitively.
As I learn new ways to use this utility I will update the guide and leave a small comment on what I changed. Same goes for if I missed anything.