With time, the home's water heater will require maintenance. You may start to observe puddles forming under the heater, or cold showers, etc. that are indications it needs repairing. Even if you are not noticing any of these problems but the water heater is approaching the end of its average lifespan, it is a good idea to ask yourself whether the cost of maintaining it is worth the money.
As well as the age of the water heater, another thing to check is whether it still has its warranty. If it does, check that it will cover the labor costs as well as replacement parts. Very often the warranty does not cover the labor which could turn out to be pretty expensive. For example, one part of the water heater that commonly has to be replaced is the sacrificial anode. This can be a difficult job to do and, if it is not done right, can damage the unit very easily. Replacing this anode could also void out the warranty. So, if the anode needs to be replaced in an old water heater, you may want to consider whether it is worth it, or if it is better just to replace the heater altogether.
To help you determine whether it's best to repair or replace your water heater, look at the amount you spend each year on average to maintain it. If the amount is more than 10 percent of what it would cost to buy and install a new one, then it might be better to replace it.
If you are still unsure about the right action to take, what not have the water heater inspected? This way you can find out the existing water heater's condition and have a better idea of whether it should be replaced or not.