I am used to pick everything up from other games and vendor it but when I do it in Fallout 3 I keep getting overcucumbered every 15 minutes. Then I need to leave wherever I am and hope there is a vendor with credits.
Is it wrong to do that? Should I just ignore everything and only pick important things up unless I need credits?
When you first start the game, you need as many caps as possible, and tend to pick up anything of value, regardless of the value/weight ratio. But once you have a stash of caps, start looking at each piece based on what it's worth per pound.
After a while I don't pick up anything worth less than 15 caps/lb, and better yet +20 caps/lb. This leave out all the useless damaged books, kitchen ware, tin cans, etc., and then then focus on weapons, armor, etc. Keep in mind some weapons aren't worth much either but can weight a few pounds each. Don't pick up damaged weapons unless you killed a bunch of raiders and use their junk for combining/repairing. Think of yourself as a caravan with only one pack animal that has limited capacity. You want your animal's cargo to be worth as much as possible when you reach the desalination.
I guess I'll stop picking up everything then and next level up I'll get the inventory talent even though I find it stupid to spec anything that isn't related to improving combat skills..
I think you got the wrong idea about Fallout3. It's not just about shooting and killing.