The Durability Mechanic by thegoldenfrog at Jan 8, 2014 2:28pm
There's a lot of speculation as to does it really matter if your backpack or shoes are "ruined" or "Pristine" well this article aims to try and gather information so it can answer a few of your questions. What do I think? I think since the game is still in alpha the mechanic isn't fully completed yet and they're still working on it, and as they work on it or I confirm more information, I will continuously update this article!
Things that May be Affected
Backpacks So what I do know is that backpacks (as of when I wrote this) are not affected by wear and tear, but I do think eventually it will be if its too damaged, you could drop items when walking around.
Clothing Now I do know for these, the more worn out your clothes are, the less they protect you from the elements. To put this in an example say you have a hoodie that is "Pristine", for the most part, it will keep you warm(ish) when it's cold outside. Now take a hoodie that is "Badly Damaged" or even "Ruined" It will not protect you as well and might be the same as if you had almost nothing on. Once again, still working on it I think.
Shoes and Gloves For shoes I believe that the more worn out they are, the less they are able to perform at what they do. Ex: Rubber boots that are damaged will not be as effective at keeping out water when walking through water. The same applies to gloves.
As of right now there only a few things that will be affected in a gun as it deteriorates, but they are critical. As the gun and it's attachments wear down, the most noticeable change is the accuracy of the gun. It will start to have a spray range rather than an exact point where all bullets go, and this applies to the bullets. Most bullets come pristine but there are a few that do not, and like with the gun, it will have a spray affect on your shots.
Optics The optics of your gun. You should really only take optics for your gun if they are "worn" or "Pristine" because any lower quality than that, and you will have cracks in your optic or other factors that make the optic useless and impossible to see through.
Silencers Well they are already realistic as in that they do not actually "Silence" the gun, its just dampening the sound and its flash. So just like everything else, the lesser the quality, the lesser the effectiveness of the silencing and flash reducing capability of the silencer.
One of the types of Items I do not know what the durability of them does, please leave a comment if you know what it is or how it's affected. UPDATE Thanks to a few of the comments below, if you read them, they talk about the food not giving as much energy if it's "ruined" and even possibly getting sick from it.