Yes. I will lose insane amounts of weight and no size, and then it will slow down, and all of a sudden, my pants will fall off.
I used to hate the thrift store. Now I like to go, just to try on jeans in sizes that I don't think will fit...then they do! I just bought a pair of 12 (Mossimo, Target, they run small, don't they? That's been my experience, anyway) and a pair of 10 Liz Claiborne jeans for $5 each.
OK, the 10s are tiiiight but they'lll fit in a while, and when my 14s are "pants on the ground" I'll be able to pull out the 10s and have them ready!