hi,
If you live in an area where there is hard tap water, then you really should be in the practice of draining your water heater at least a few times a year. Draining the water heater gets rid of the hard water mineral and rust deposits that build up and reside at the bottom of your water heater's tank. The longer this sediment sits inside the tank, the shorter the life span of your water heater will be. Not to mention the agony of cleaning sinks, showers and tubs with rusty mineral build up!
Thanks,