Do strippers have good and bad boob days?

You know, kind of like good and bad hair days. I don't generally notice this in a short period of time, say a few weeks or less, but sometimes i'll see a dancer a few months later and her boobs will either look significantly better or worse. Now, i know there are a plethora of factors that could cause this. Weight gain or loss, or even muscle gain or loss, hormones (birth control or pregnancy), supposedly ovulation and menstrual cycles has an effect as well, lactating/nursing breasts definitely has an effect, particularly the nipples. And of course having a baby. I'm also generally describing natural breasts although fake ones are also affected albeit not as much. But sometimes, none of these mentioned factors seem to be in play and then i'm a bit intrigued. Anyone else notice this?