If you need to get a water heater, the one that you choose will be important. Go with one that's too small and you can end up running out of water mid-shower. Go with one that's too large and you can see your energy bill rise substantially. In some cases, a tankless water heater can be a great choice, and here are some examples of households that would do exceptionally well by having a tankless one installed: 

Your hot water usage fluctuates

If you have a household that can demand different amounts of hot water regularly, then you can find a tankless water heater to be a very good option for your house. The reason for this is that on the days when your household is requesting less hot water, less hot water will be heated. This means less system wear and lower energy costs. On the days when your household is needing more hot water, then more hot water will be produced. It will be produced at the amount needed, and this means no more jumping out of the shower in shock as it suddenly becomes cold. 

You don't have the room for a discreet hot water heater

If you have a very small home or if your home doesn't have an appropriate water heater closet or area to store a tank where it is out of sight, then you may feel you just have to accept it being visible to your guests. However, this isn't the case when you have the option to go with a tankless water heater. A tankless system has components that are much smaller than a tank. In fact, they are so small that you may be able to hide them under a sink or behind something in your home to keep them out of sight. 

You don't want the maintenance of a water heater tank

If you live in an area with very hard water, then you can find yourself needing to have your tank drained to remove sediment often. Plus, you have to watch the tank for problems like leaks and other issues. Tankless water heaters don't tend to need as many repairs because of the fact that they aren't constantly working to heat water even when no one needs it. A tankless water heater is your best bet when you want to think about how you get your hot water as little as possible.