This sums it up nicely. Also, if it's easy and you've done it a million times, charge an inflated fixed price. If it's new territory, charge by the hour. Edit

This sums it up nicely. Also, if it's easy and you've done it a million times, charge an inflated fixed price. If it's new territory, charge by the hour. Edit: before I forget, if you let them know how it's done then you need to charge for the several times they won't come back again afterwards.