Spacelord,
Some states have a code for how often you are required to service your equipment. Your insurance provider may as well. With that said, asking how often it needs to be service depends on your equipment and the frequency of use.
If you are looking to save money, this may not be where to look. The elevator in your building is still part of the investment you made in the building. If someone is hurt using the elevator, the lawyers will chew you up for not maintaining your equipment.
I recommend reducing your expenses in another fashion.
