Tube amp on/off: best practice?

Polk432
That's how I do it.

Soundgasm
The 9 pin tubes stay on all the time in my amp and on standby in the preamp, it's been the "big" power tubes in the amp where I've had problems. The last power tube that failed, a 6C33CB, started to glow cherry red, and the one before that started arcing. I haven't had anything catch fire and don't intend to tempt fate anymore even though my amps take 1 1/2- 2+ hrs to hit their stride, "settle in" and start sounding very good, at 3+ hrs the magic really starts to happen!!!

I would say since you a leaving and then coming back I would power off just in case of a problem devolping and you are not there to resolve the problem.

The on/off is supposedly harder on the tubes than just leaving them on. However, a tube blowing is scary too. You are in a "no win" situation.
For that same reason I went with solid state in my office. I just leave it on all week now. If that were tubes and they were totally safe, you would still be stuck retubing once or twice a year!
Save the tubes for home or serious listening only.

I agree with the above about not leaving the room when tubes are on, they most certainly don't always go quitely.

The best advice by the tube sellers I buy from is to conserve tube life by turning the amp off. I also asked about the power up cycle as potentially leading to excessive wear on the tubes. The answer is that most amps nowadays have a soft start cycle to blunt whatever the power surge may damage. The other concern for me is that I am fond of old stock tubes which as everyone know have become scarcer and scarcer. Therefore I really do my best to preserve them.