there is a school of thought that says that the temperature difference in heating and cooling when switching on and off, is worse than the relative constant temperature of leaving switched on all the time, from a reliability point of view. There may be something in that for poorly designed and badly built (soldered) components, a good design it should not matter. Others say permanent power leads to a shortening in component life.

there is also a school of thought that sound quality is better if electrolytic capacitors and A/D and D/A converters are powered permanently.

check your insurance policies for fine print about fire hazard! you could fall foul in case of disaster.