Sediment build up over time can reduce the efficiency of your water heater to the point where you notice you're not getting enough hot water, especially if you are demanding hot water from more than one or two spots in your home. Other culprits can include temperature sensor failures and problems with the heating element. Water heater manufacturers recommend that you schedule regular maintenance checks with a licensed plumber in order to keep your system in top condition. Industry estimates for water heaters are between six and 13 years for conventional tank water heaters. Tankless water heaters tend to last longer.