I do the same and I have actually used a lot of them again because I always forget that I actually wanted to buy some screws in different sizes, so I just make due with whatever I have at home since the urge to do stuff usually hits at 2 am, when you can't buy screws like right now.

I do the same thing with cables. I was holding onto a phone cord for well over ten years (no idea where it came from in the first place) and finally tossed it out after telling myself there will never be a need for it. Guess what I needed two weeks later?