Always a problem.
When I bought my first 2002, it came with a few boxes of spare/old/who knows? parts. And I added to that collection when I replaced the interior and did other work. Then I got Hoodlum and have been taking bits off of it at a fairly rapid rate.
So I am awash in old BMW bits, some good, some not so good. Some I'll want to keep for spares, some might bring in a buck or two, some are just junk. The problem is, it'll take me a full day or two to do a decent inventory and figure out which is which, and who wants to spend a who day doing that?
Telling myself that winter is fast approaching (despite yesterday's 98-degree high) and it'll make a good rainy-day project. In the meantime, thank goodness for storage space!