Stage 3C Patient
Everyone is different of course. The amount of fluid that comes out is when they can remove the drains. It does not hurt when they are removed :-) the surgeon will give you measuring cups for when you empty the drains. Once the fluid coming out is little enough, then they can be removed. If taken out too soon, it can cause serum which will later be annoying and have to be drained. I was told women with larger breasts take longer to drain.
Beforehand, you can prepare by having needed items at home, or where recovering, lower than your shoulders. You can't put hands over head! We bought loose button front pj tops-- I lived in those! We sewed pockets to the inside of the pj tops for the drains. On one we just used double sided tape and a square of fabric to put pockets onto a shirt (button down) for me to wear. The cami with pockets was ok but tight. I didn't need tight since did not have immediate reconstruction.
I used baby wipes for cleaning self since you cannot really shower with drains. They are a pain, but you also get used to them. Good luck!