I say blow dry. It makes parting and braiding easier. Yes it may not be a bother for diy'ers to braid on air dried or even wet hair but consider that commercial hair braiding is different than chillaxing in your bedroom or living room or bedroom for hours doing your own hair. Someone who has to stand over your hair for hours installing braids may not do her best job if she has to spend a lot of time prying through it and detangling as she goes. You should also ask your braider what she prefers. Some will say blow dry or press - and some don't care. A blow out with a good blow dryer takes all of 5-10 minutes and is not harmful anyone's hair. Your hair will bulk up a little bit when you first wash it (or when water hits it) but not much coz it's encased in extension hair.