Yeah, don't fall into the trap of thinking you've got to get them all. They're NOT Pokemon. Treat yourself to one or two here or there. On new titles, I tend to get variants as they may help fund further purchases down the road if I sell them, but most of the only variants I get on existing titles are usually only Spider-Man and Batman.
Indy's CGC Comic Gradings Master Thread --> http://tinyurl.com/p45agbh