OK, so I'm nowhere near HRT at this moment in time, but one key thing I've thought about recently for when I eventually do start is breast growth.
A lot of sources seem to conflict on what the eventual size will be. Some sources say it's rare for breasts to exceed an A cup, while others say you can expect breasts around 1-2 cup sizes smaller than your mother's. For the record, I'd much rather the former be true - A or B cup would do me just fine, and all the women in my family have F-G cup!
Furthermore, it's worth noting that I have pectus excavatum, which I imagine will probably make finding bras that fit more difficult...
But yeah, primarily I'm concerned as to what general size I can expect - if the average woman in my family is F/G cup, does that mean I could end up with D/E cup breasts? Or (as I hope is the case) is it likely to be a lot smaller?