I tend to sleeve my LCGs because it can be hard to find some of the expansions down the road so if cards get messed up they can be hard to replace. I don’t sleeve any other games (unless they’re rare or something).
It’s really not a big deal and I probably shouldn’t, but I have it in my head that, someday, When these games are out of print, I’ll sell my pristine copy and get my money back. Of course, I’ve never sold any of my Lcg cards, so this is merely a way for me to justify buying all these god damned sleeves.