As a result, I think this might be a worthy thread for the Construction topic since I suspect more than a few of us have this kind of kit either purchased second hand, or maybe even in some cases just plain sitting in the stash for a long, long, time...like since 1981 or so

Special case that comes to mind immediately are things like old decals. As these things age they do become more yellow. I've seen people suggest exposing a decal sheet to sunlight will whiten it back up. Decals also get more fragile with age, but I've seen some people say that you can overspray these with clear to strengthen them. Is this true, in which case clear what?
There's also issues such as partial assemblies. To some extent this thread might help: Deconstruction. I do understand that the plastic itself on some older kits might not be in as good a shape. Any worries there.
Probably the most problematic physical part issue might be canopies and clear parts in that clear is brittle to start with, and bouncing around in a box for 30 years might just put more than a few scratches on these. Any advice there?
I realize this posting is fairly general, but I figure it might be helpful as I said for aging kits and old stash kits that remain unbuilt - regardless of the unbuilt collector status for these things. Personally I'm more of the mindset I'd like to see the thing built.
My own immediate questions is indeed the decals issue. I know that I can buy stuff to make my own if I got a color printer handy but even there white is a problem (short of working ALPS). Are old decals really just scan-worthy or can they be re-used. Sometimes its just an issue of old decal left-overs from other kits that might make good detailing on other kits.