This article in the NY Times hit home with me (and thousands of other women, no doubt). This chart shows some of the "sizeism" in fashion- and the variations in sizing aren't always cost- driven.
Another pet- peeve? The naming of styles. How am I supposed to remember that the "Charlie" or "Hooker" or (insert random name here) jeans are panty- bearing rise and no hipped, with skin tight legs? And while I'm probably technically curvy (though more on the top than the bottom)- no "curvy" style of pant has ever fit my 33" inseam - in flats, no less- or my fairly flat butt.
Sure, I wear tons of vintage clothing, so I expect a huge variation in sizing from yesteryear's styles to modern clothing. But it would be nice to walk into a store and be within a two size range. Until then, I'll stick with the brands that (usually) work for me. And plan on taking armfuls of basics into fitting rooms.
Do you buy based on that little number on the tag or based on what fits?