I'm working on several long runs, and consider myself a run collector, but the space issues with keeping several runs of 200-300 books are getting a bit impractical. I may need to make some difficult choices moving forward. A lot of the runs I am collecting now, mostly pre-hero Marvel, are pretty expensive in the 6.0-8.0 grades that I am trying to buy them in. The challenge is fantastic though.
Years ago I toyed with the idea of collecting every appearance of Spider-man, my favorite character. I still think that this may be practical if you stuck to, say, pre-1975 or pre-1980 appearances, but in the 1990s when crossovers got ridiculous it becomes pretty insane to try to keep that up.