Is it necessary to circulate hot water in home improvement?

Domestic hot water circulation system (commonly known as water heater, backwater device, hot water reducer, circulating water, hot water circulator, hot water preheater, preheating circulation system with embedded return pipe and without embedded return pipe, etc.). ) is a kind of water circulation device, which solves the problem that the central hot water system can't use hot water with suitable temperature in time before the hot water is used (commonly known as cold water discharge) because of the long pipeline.