Way back when I started losing weight on January 21, 2007, I bought a pair of jeans in a size 12 as a tangible motivator of the new body I was working towards. I got a size 12 because it was a size that I felt was attainable (considering I was a size 32 at the time, anything smaller seemed like too big of a leap). A lot of people told me that it was silly to buy a pair of pants that much smaller than my current size and that it was a waste of money, etc. etc. Well, they were wrong. I got into them. And I got them buttoned. And zipped!
They're still pretty snug, so I'd want to lose maybe 5 more lbs before wearing them out, but I got them up and I didn't have to struggle!
At the time I never thought I could possibly be smaller than a size 12, but here I am, still truckin'!