Hoarding

OP-2 is a game about hoarding, among other things. This page attempts to explain the mechanics related to collecting items in the game.
== Is hoarding really required? ==
As explained in more depth on this page, it isn't. All these chain/hoarding quests are optional and only required for a single questline and achievements. Some chains also feature good rewards and can be done with relative ease, though.
However, many missions throughout the mod ask for random items in random quantities, ranging from trivial to gather to very annoying. For example, 30 PDAs, over a dozen 9x39 boxes, an Anomalous rifle and Cloaking Exoskeleton and the weapons and artifacts required for the optional, but very powerful modified shooters which may be assembled by Vasily and Lanky.
== Standard containers ==
Standard containers you see throughout the game are limited to 50 items in their capacity. This is done because the X-Ray engine can't keep up with the massive amount of items players tend to keep in one location.
There's an item called Lock, obtainable from Akim. In older versions of OP-2, it was needed to reduce the probability of NPCs stealing from standard containers. Since OP-2.1, they don't steal from standard containers anymore, so the locks are useless. 10 locks are still required for Doctor's chain quest, though.
== Rucksacks ==
Throughout the game, you will obtain Rucksacks. They can be dropped onto the ground to create custom stashes. Rucksacks are highly optimized for hoarding and you can easily keep thousands of items inside them. By default, they feature a list-based interface; if desired, they can be switched into the classic icon-based mode. List mode has a (rather generous) capacity limit as a holdover from 2.1, while icon mode does not; both modes have their use cases, intricacies and downsides which won't take long to figure out. Each backpack contain a GPS tracker and can be seen on the PDA map, with all its contents displayed in a tooltip. 
The best way to store your Rucksacks is in out-of-bounds areas that people will never come to, such as the Bar's vast out-of-bounds areas on either side of the Southern road.
== Theft ==
NPCs occasionally steal items from your backpacks when you aren't around, even in remote locations. There's no point in hiding them because NPCs don't have a concept of obstacles or height when looting. They exist on a 2D grid, and have a certain chance to steal a backpack if they happen to come within 25m of it. Keep your stashes away from typical stalker routes to not have them stolen.
The best way is to place your stashes out of level boundaries. There's no navigation mesh there, and your possessions are safe from NPCs. Many levels have easy OOB exits in OP-2, especially Bar, so this can be easy. However, on many locations OOB exits are complicated enough to make that impractical. The edges of maps or areas with zero foot traffic are usually 100% safe or extremely unlikely to be stolen before you can do anything to stop it.
If the backpack is stolen, the GPS tracker still keeps tracking the thief movements on the PDA map, so you won't lose any items. You'll have an option to buy the contents back from him for 50,000 RU, or to kill the thief and grab the lead note from his body. The lead note is encrypted; any trader could decrypt it for 60,000 RU. In either case, your stash will return to its place automagically, there's no need to haul everything back.
NPCs don't steal from vanilla containers, with the exception of a couple bugged ones (the box near the campfire at [ abandoned farmstead] in Army Warehouses being one example). But these containers are limited to 50 items to avoid hogging the engine with the unbelievable amount of stuff OP-2 has.
== Guarded stashes ==
Dropping a backpack in the vicinity of a trader will create a guarded stash. You'll have to pay 10,000RU initially and 500RU daily for each rucksack you drop, but the trader will keep an eye on it and guarantee that it won't be stolen.
The daily fee is not particularly steep, but can be a problem in case you ever fail to pay: as traders typically have other stalkers around, your stuff is likely to be stolen immediately, maybe even by the trader himself.
During the game, you'll have a few moments when you discover your money temporarily stolen, for example during Holdup. The quest typically lasts under 10 minutes, but if you're particularly unlucky, your trader can decide to withdraw the fee during this short period and fail, removing the guard and making your stashes free to steal. The entire Valley of Whispers storyline lasts more than a day and will guarantee your stuff losing the protection during it.
For this reason, it's not recommended to use guarded stashes at all.
== Carrying weight ==
During the game, you will increase your maximum carrying weight by various means - armors, artifacts, and consumables like "Hercules". Carry weight artifacts are in limited supply and can be given away about as quickly as they are obtained, despite remaining useful even into post-game, think twice before parting with them without adequate compensation. One notable way to increase your carrying weight is Grav-suit, which is a reward for Unique suits, a quest given by Skinflint. It can be further upgraded later in the game.
== Bulk transport ==
There are working vehicles in OP-2. You can use them to transport large amount of items, as you can drive with any amount of items in your inventory, regardless of being overloaded.
Vehicles have infinite fuel, but drive terribly and are vulnerable to damage. Each vehicle has unique handling, damage tolerance, killing potential, etc. Early game, they're a hot commodity, though most of them lose their usefulness as the game progresses. Vehicles can be teleported with and come with you, though this is only applicable for a few maps due to the teleport destinations themselves and the usefulness of having a vehicle present in the map; at least one mission can be greatly expedited with this mechanic. The "bread loaf" UAZ found in ATP seems to be invulnerable.
When teleporting, your maximum carry weight is ~90kg higher than the displayed limit (~80kg higher than the overencumberment limit). If you don't care about indulging in the cheat menu options, you may toggle infinite teleport carry capacity. 
Category:Core mechanics