Sunlight will deteriorate nylon. after leaving them out all year, I'd replace them.

Some straps are eaten in no time by critters. Others are ignored. I don't leave mine up but do have a ladder stand that's been in the woods for about 5 or years. I walk by it every once in a while. The aircraft grade straps are great but the squirrels are chewing the heck out of the bottom of the plywood platform. I have NO idea when someone sat in the thing last. I also left a hang on(chain on) "Loc On" in the woods for about 4 years. The tree had grown so much I couldn't get the thing loose. I finally managed to break the chain out of the bark that had grown around it and move it up the tree enough to undue it. I mean I grunted and huffed and puffed on that deal. Screws rust and sometimes the damage can't be seen inside a metal tube. You can't just put any old screw in those things. You want as hard as you can get.