"For longevity it's got to be leaving it on BUT what if the difference was 10 years for on/off or 20 years always on? Do you really think you're going to keep it for 10 or even 20 years?"
... I respectfully beg to differ from the right honorable contributor and friend Tbg. New-ish hi-fi gear actually breaks all the time and my crusade to get the truth out about this issue is explained mostly by my desire to avoid buying a used product that has been misused through repeatedly being turned on and off, and which is thus much more likely to break in my hands, causing me expense and aggravation.
Don't get me started about other misnomers in this hobby. Ads for gear being sold by the "original owner" that has "only been used thirty hours"??? This means that the seller is either a liar (and, therefore, God knows what he's selling) or an ignoramus (and I'm going to have to run the virgin in question for hundreds of hours with a break-in track before it sounds right). Like I said, don't get me started ... but I WILL say things about:
... People selling preamps and phono stages that their ads display sitting on top of subwoofers.
... "This product is an original Mk. IV, not an upgrade" -- as long as the upgrade has been broken in, totally irrelevant.
... "Reviewed favorably by HP in last month's Absolute Sound" -- every single component or speaker that windbag reviews is the next great step forward in the advancement of reproduced sound (excuse me, I meant the advancement of "continuousness"). For that matter, aside from Cordesman, when was the last time that magazine published a review that contained some real substance and that was not incredibly flattering? The difference between TAS and Stereophile has become striking (Stereophile reviews being much more detailed and, of course, featuring extensive measurements). In my opinion, TAS has become a sham and I've stopped subscribing.
