Mine lasted almost exactly 5 years. It blew two weeks ago. If it is electric and you do not replace the sacrifice rod, they will blow out the plug on the front of the water tank. Hopefully you will be home when it blows. This is not piculiar to Smith but with all electric heaters. My GE replacement heater is gaurenteed for 10 years, but it has two rods. The plumber states it is the same as the first heater, but has two rods to make it last twice as long. Replace the rod every 4 1/2 years and save yourself some problems.