Does my new water heater require annual maintenance?

You bet it does. If you want your water heater to last you as long as it possibly can, you should have the sediment drained from it twice a year and have the safety valve tested at least one time each year. Another thing you should have determined is whether or not you need a thermal expansion/ bladder tank installed. If you have a backflow prevention device installed on your water service then you should have a thermal expansion tank installed. If you already have a thermal expansion tank, then it too should be inspected yearly.