I been thinking about this for awhile now. My bed was pretty expensive. ($700+) Its one of those pillow top ones, and very firm since my back is all messed up. After about a year I started noticing an indentation where I normally lay...same on the better half's side. I don't know if its the pillow top or mattress itself. Doesn't seem to be the pillow thing though.
Really like the pillow top, but now I see the drawback. You cant flip the mattress! And switching around the head/feet of course doesn't help either.
I'm with you on this one fartness...they might make it sound like they got the science down on mattress's, but I call BS on it.
This isn't the first time I have gone through this with an expensive mattress.