There probably is, but I'll give you some off the top of my head.

#1 always make sure speakers are connected. Tubes need to be connected to something. Amp and/or tube damage could result in trying to drive an open circuit.

#2 Tubes are analog, give them time to warm up, time to cool off, and they get HOT. Handle with care, try not to swap them when hot (they break easier when hot), don't forget the amp on for days on end, etc. I enjoy the ritual of coming home from work, powering the amp on, going to change out of my work clothes, and it's warmed up by the time I'm in my comfy clothes. And the sound is even better after warming up even more with actual music!

#3 Have a spare set of tubes; basically for diagnostic purposes. If you notice something not right, a crackle in one speaker, volume difference left to right, no sound etc - you can swap in your spare set to help diagnose if it's a tube issue or something else. It's also nice to help you gauge how tired your tubes are. Tubes age slowly, so much so you probably won't notice when they are "getting tired" and need replacing; so after 6 months, pop in your spare set and see if the sound is "holy crap" different or marginally different, or no difference at all. When you get that "holy crap this is better" then you know for sure it's time to replace tubes...don't wait for them to to die like an old lightbulb (which could damage your amp).

#4 Again, tubes are analog, and made by hand in China or Russia (usually). Expect changes, random dead tubes, aging at different rates, sounding different as they age etc.

Lastly, just enjoy listening! A lot of Transistor guys will poo poo all of the above because "it's too fiddly", or "not accurate", or "too much distortion" or some such... but we wouldn't be doing all this if it wasn't worth it. The sound is truly amazing, sometimes transcending, so really enjoy the music and don't worry about the fiddly bits too much. Just be safe, buy good tubes, replace them when needed, enjoy the music.

Good advice so far, I can only add be patient, my system gets used almost every day and now going towards 2 years still gets better to me. I’m pretty sure most of it is my own ears refining as opposed to equipment breaking, but it is what it is and it’s an amazing transformation.
Enjoy,
Scott

The reason that the tubes break easier when hot is because you inevitably drop the tube because it scalds you. It has nothing to do with the physical properties of the tube but more about the amount of pain that you can endure!

I am guilty of swapping out hot input tubes when tube rolling.

RULE: Never use your bare hands when handling hot tubes. Use a cloth or paper towel between the tube and your skin.

I agree with Donnie on the scalding thing, that's usually my method of retiring tubes...the "hot drop".

As for military applications, there is a big difference between a tube mounted in a rubber isolated tube socket in a jet, and you squeezing and/or bumping the hot glass envelope while it's at operating temperature. In a military application nothing is touching/bumping the glass...and if it is, you have bigger problems to worry about.

Nah, the internal structures are spot welded together, and the military grade tubes usually have more mica spacers to keep them from rattling on the inside. Military tubes are often shorter, thicker glass, etc to help harden them.

Now compare that to the Chinese tubes of today....