Many clients ask how long a water heater lasts. The "blanket" number that they put on water heaters is 10 years, but there are a lot of factors. For instance, electric water heaters tend to last slightly longer. Also, some brands last longer as well. Either way, if your water heater is older (such as the one in this picture) you should watch it closely and be proactive and replace it before it finally does reach the end of its useful life.