I hold a traditional belief that electronic components are subject to wear and tear, potentially shortening their lifespan if left turned on continuously. However, frequent power cycling can also stress certain components like relays. My first integrated amp, Harmon Kardon avr25 ii, has served me well for 28 years and still performs admirably. However, the relay may need replacement in the future to eliminate the minor, yet annoying, pop noise it produces when initially powered on.
While I don’t believe this pop noise will harm anything, I’ve adopted a temporary solution to avoid it. I disconnect the negative terminals on both speakers and reconnect them after the amp is powered on.
I would recommend leaving the system on if you use it periodically throughout the day but consider turning it off when you’re done for the day.