It can be a LOT shorter, but Crashem's got a good guideline.

Make absolutely sure that you don't hear any servo "buzzing" when the controls are centered or moved though their normal ranges. pay speical attention to the throttle, make sure the buzzing doesn't happen at any point, espeically full throttle and idle/engine kill settings.

That servo buzzing is a stalled servo, and it's eating battery charge like crazy.