New to tubes have questions

1) No. But the sound may not be all that pleasant. I typically turn on my system and let it warm up (with music playing) at lower volume for about 30 minutes.

2) Yes. A couple of minutes for initial setting, and then after about an hour or two for final setting. Check your bias regularily (every couple of months) not only for maintaining optimum sound quality but you will also note tube wear.

3) Without knowledge of your amp, generically I would suggest that since power tubes can fail suddenly and they can be a PITA if they take out a resistor when they do, that you watch the power tubes during the first minute or so of warm up - if you see the plates starting to glow red turn it off and put in a new tube. Tubes shorts usually happen at initial turn on, but when walking by the amp from time to time its a good idea to check the tubes for any red glow on the tubes. Also listen occasionally close to your speaker with only the amp on for crackling sounds (not tube rush) which can reveal either a driver tube getting noisy or a problem with a power tube.

Don't get anal about tube rolling. Excessive tube changes can cause solder joints etc in the tube sockets to fail. Also, try not to rock the tubes to extract them, for the same reason.

Hope that helps a bit........

To answer these questions.(1)It won't hurt the amps to play w/o warm-up,though 5-10 min to let them idle won't hurt either.Most tubes take 30-40 min to sound their best,with the performance elevating from that point on.
(2)About the same period before biasing.Let it stablize.After about 2-300 hours the tubes should be broken in and not need daily biasing.This will be dependent on the quality of the tubes.Generally speaking NOS perform better than the new generation of tubes,but there are exceptions.
(3)Don't turn the amp on/off quickly-watch for tubes glowing brighter than the others.
Hope this is helpful.Enjoy!

3. Don't turn your amp off and on, off and on...Did you ever notice how light bulbs fail when you turn them on? Similar situation here as mentioned above. Turning your amp on is stressful to your poor little tubes. Keep the on and off to a minimum.

The biggest "don't" is never power on a tube amp unless it is connected to a speaker.

Gs5556 and Pawlowski6132 named probably the biggest don'ts.

If you get a tube amp that has a power on switch and a separate standby switch, be sure to follow the owner's manual and don't turn them on in the wrong order.