I would say this is very useful for keeping track of tips and hours, but it needs a way to calculate overtime hourly when we go to time and a half after so many hours. I would also add a way to calculate a rough estimate of taxes etc. that are taken out. That way I can compare my paycheck with what my estimates are.
But I do like using this better than writing amounts down where I might lose them.
Captain41 about Tip Mule