When u have built up a regular clientelle. And you are always busy friends will stop messing you about. My friends know they need to book in advance and they know they will pay, in return i do knock a bit off but they usually come when it suits me not them, my friends actually winge that they can never get an appointment! And my poor mum book a month in advance! I used to say I enjoy doing your nails but this is my job. I have a mortgage and children, its a bonus that I enjoy it and if you have a nice day at work you still get paid! We all work for one reason only and that's money!