I think the key for me is (a) never making fast purchases, and (b) keeping my eye on curating a small collection of great smokers instead of a large collection.
I own more pipes than I smoke, and I suspect that even if I had a collection in the triple digits, I'd still primarily smoke my 5-10 favorites. These days, I have several knock-around pipes and about ten 'good' pipes. I'd still like to buy a new pipe every day, but when I take a step back and think about it, I realize how silly it is.
Smokingpipes' wishlist is a fantastic tool to curb PAD. If you see something, pop it in there, and wait a week. If somebody else buys it, it wasn't meant to be. If it's still there after a week, assess again whether you still want it more than you want anything else you could have bought with your money.