I'm trying hard to stop buying stamps. I have tons of stamps. I love them. I really can't say I need any more.
But what truly influences me is the blogs I read. I fight it by telling myself, "Erin you can make a similar project with stuff you HAVE" And I very rarely CASE a whole card anyhow. But when I see the bloggers I love making adorable projects with new stamps I get the itch to get those stamps. So in those cases I try to wait. Maybe a month or so. If I'm STILL itching for the stamp then I get it.
Pretty much every time I've seen a stamp and said, "ohmyheck I have to have that" and bought it right away I've barely used the stamp. Sometimes I'm over it even before the package comes to my home.
One thing I don't let influence me anymore is price. Now of course if some stamp was grossly overpriced I'd have to refuse to buy it. But in the normal price range of stamps I think it's far more important to get what I'll use than what is a "deal". And if I didn't want it at full price I figure I still don't need it on sale ya know?
Finally I don't buy special stamps because so-and-so would love them anymore. How many cards for so-and-so with the same stamps am I really going to make? So I get what I really like. So-and-so can appreciate a handmade card from me made with my favorite stamps or they can drive their happy butt to Halmark and get their own special card. lol