I've said it before, and I'll say it again, any time I've bought a knife on impulse, I've ended up regretting the purchase. And, more often than not, I'll end up selling it for a loss. I kinda follow Jim's method, and I'll wait a bit before making the purchase. If, after a few weeks or a month, the knife is still in stock and I still want it, there aren't any other large expenses looming on the horizon, and I still have money in my PayPal account, then I might buy it.
Another aspect that's keeping me from spending money, is I have very specific attributes I look for in a knife, and right now it's hard to find a Spyderco that has all of those.
I have a blog! http://thestuntzombie.com/
Haves: Manbug Salt, Lava, Delica 4 Sante Fe Stoneworks, Spy-DK, Wharncliffe Delica, Ti Squeak, Delica 4 Combo Edge, Salt 2 Wharncliffe, Worker G-10 Sprint, Wharncliffe Dragonfly, Ti UKPK.