Based on the manufacturer’s suggested service life, the life expectancy of a water heater is about 8 to 12 years. That varies with the location and design of the unit, quality of installation, maintenance schedule and water quality.
If your water heater is more than 10 years old, leaks around the base of the tank, and / or works erratically or not at all, it’s probably time for replacement.
If you’re replacing a water heater, you can replace it with the same type of unit. However, upgrade possibilities should be considered. For example, you may choose to increase or decrease the unit’s holding capacity to accommodate a changing family.