Don’t waste energy and money heating the water in your pipes. When you need to use only a little water, such as when you rinse a dish or your hands, use cold water. It can take several minutes and several gallons of water running through the pipes before the water at the sink is warm and by that time, you’ll likely be finished. What you end up doing is running a little hot water into the pipes where it will just get cold, and depleting the tank of a little hot water which will then be replaced by cold water which then needs to be heated. Keeping the lever in the hot position uses energy to heat the water even though it may never reach the faucet.