How long are you willing to wait for your water to get hot? Some of us are impatient and want the hot water to start streaming as soon as we open up the faucet, but still, there is a point where it gets ridiculous. If you have very long pipes going from your water heater to your faucet, the wait can get long, and you will be wasting a lot of water just leaving it running for a while.
There is an option that will give you instant hot water, and that is a hot water recirculation pump. There are 2 different ways in which this works, either with a dedicated loop or return through the cold water pipe.
Just like the name indicates, a hot water recirculation loop will take the hot water from your water heater and circulate it through a pipe to be available to use whenever needed. If it is on a dedicated loop, the water can just circulate freely, but if it is returning the hot water to the water heater through the cold water pipe, then you might not have quite as satisfactory results.