If you are at home all the time listening to music (avid music lover, audio reviewer, etc.) then leave them on. Tubed equipment would be the exception. Unless you don't care about replacing expensive tubes often. Each manufacturer recommends the number of hours that the tubes should last before replacing them (before they fail dramatically and take out something way more expensive). If you listen occasionally or don't care to come home to a house fire, then turn them on when you are about to listen and give yourself 30 minutes to an hour warm up and you are good to go. Assuming your equipment is already broken in. Being an electronics engineer, I can tell you that the saying in our industry is that a $10,000 circuit will protect a 5 cent fuse by blowing first. So, when a tube really fails, it could cause some dramatic expensive repairs. So, it is better to replace tubes on the recommended hour life before it fails. Same with car parts, eh? This is called preventive maintenance. But, if you are home most of the time, leave the Rowland equipment on. If you have to step out, turn if off and turn it back on when you get home.
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