I just take the money after each booking (or day) and split it 3 ways into different places:
money for the house and bills, food etc in my purse
money to save in my saving tin in the drawer
money to treat myself with - in a separate purse for my next shopping trip!
If i don't do this i just spend it recklessly.
It's a good idea to keep track though, that way you can see a pattern of which days/weeks/months are busier and take your days off on the quiet days(although you can probably see the pattern without keeping a written or computer record). The massage place i work in one day a week has everything all organised and they have a TON of paperwork to do all the time though. x