I find that after so many years away from building, when I see box art of a kit I built as a teen, I am drawn to that kit like a moth to flame, and must acquire it. or seeing one I remember as a kid, but couldn't have/afford, makes me want it [regardless of kit quality].
I hit model round up pretty regularly, and have a good wish list, it seems to go in stages, what I want 'now', what I want eventually, and what I would get when the time is right. oddly enough, most of what is on my list, are the kits I did as a youth, or what I couldn't afford as a youth. isn't a lot of 'new' kits that strike my fancy.
seeing some box art takes me right back to a place in time, my mind recreates the smell/vision/feeling of when i built it the first time, hard to describe, but i know some of you have experienced the same thing.