We hear often about sizing here on 3FC, and indeed that is one of the ways that we (I, at least) measure our progress. Right now, I would count myself on the the low end of 16 or the high end of 14. Those sizes are from my storage bins as I've worked my way back through sizes; I did this journey once before, 7 years ago, when I got to 170 and then quit. (Dummy.)
Styles were different - they were higher-waisted - and sizes were a bit smaller. So, if I'm wearing a 14-16 in my closet, I found that I'm wearing a 10-12 at the store (using Levis as my metric) when I'm shopping. I was amazed at how much sizes have grown.
Okay, we've all read or written about vanity sizing, right? So far, so good - sizes are bigger than they used to be. But it finally dawned on me, for real, that I wasn't "cheating" in wearing the size 12 jeans, because the jeans are styled so very differently. Mid-rise Levis don't have to deal with my thick-ish waist and very much flatter my much-nicer thighs, hips, and backside.
My old jeans might fit in the waist (finally), but they bag out everywhere else. Well duh! On the size charts, all my measurements put me right on the line between 12 and 14 except my waist, which is always a size or more larger.
You will probably laugh, but I
finally get it about shopping for clothes that flatter your figure as opposed to shopping for clothes that fit.
For a woman with a PhD, I can be remarkably slow sometimes.
Sizes and fit
And yet, I know they are. Depends on far back you go though. I'd venture to say my current 10's are about a 2000's 12's. 
See, there's just no "getting it". I just want to be the size I was when I got married. In 1998 I was a size 10, whatever that equates to today.
It still feels a little bit like cheating, and I totally felt like an impostor looking for 10s and 12s in the Misses section of the store, but you're right about the boost! It's pretty startling mentally to go from a size 16 to a size 12 in 30 seconds or less. 
