Reply #4: It's weird.

[eyesroll]

I'm 5'2", 120. It seems I can wear a "medium" top from no matter where (I guess there's more leeway), and I have some wiggle room with dresses, but with pants/skirts it's all over the place.

At Target and Old Navy, I'm a 4p.
At most mall stores, I'm a 6p.
Thrift stores, I'm usually an 8, because the stuff there is older, from before the sizes went bonkers.

I went into a 5,7,9 Shop 10 years ago (when I was still in college), and nothing fit -- I told them I was normally a 7, so what was the problem? They said, "we're a junior petite store. Our 9s are like most people's 3s. Good luck."

I can't really wear Juniors (petite or otherwise) anymore, because the proportions aren't right for me.

I have the best luck shopping vintage or thrift, ignoring sizes and just eyeballing what looks like it's going to fit. It usually works.