Do I need to maintain it? How often?

Do I need to maintain it? How often?

You should have your hot water system serviced regularly – you should have service checks regularly. Even minor issues in hot water systems compromise their efficiency, and major issues result in costly repairs that preventative maintenance could have averted. 
If you have a vitreous enamel tank, you may need to change the sacrificial anode about every 5 years depending on your water quality. 
Your hot water system should be serviced according to the user manual.