[brudgers]

My advice:

1. If it is reasonable, consider delivering the work the following day unless there is compensation for for fast turn around. Otherwise, when busy enough that a project cannot be completed the same day, the client's expectation of same day service will still be there.

2. The agreement with the client should state the minimum amount to be invoiced (for example one day).

3. Invoice along with the completed work so that each project remains separately billable.

4. Raise your rates per Thomas 'patio11' McKenzie.

Good luck