Also, if you really want to maximize what you earn, specially if you work part time, is to charge fixed price. Because pricing not only depends on how much work

Also, if you really want to maximize what you earn, specially if you work part time, is to charge fixed price. Because pricing not only depends on how much work needs to be done, but also how much the client wants it/how fast they want it, and the ability for client to pay. Some client care too much about pricing, some clients doesn't care at all. Even in second bunch, its hard to inflate hourly price. But for fixed pricing, there is almost no limit on how much you can charge.