If you don’t see much sediment when you drain the tank, don’t bother to do this chore very often.
Use extreme caution when draining hot water heaters—the water might be hot enough to scald you. Direct the drain hose to a safe drain, so the tank can drain without causing injury or flooding. Instructions are printed on the unit, usually near the gas valve. But, this is a chore that not everyone is comfortable with. When in doubt, get help—have a service professional walk you through it the first time.
If you have an electric water heater, it’s critical to shut off the power before emptying the tank—if you don’t, it will destroy the heating elements.