Very interesting dilemma.
I have a similar set up.
I have the Ref 40th anniversary, similar to your Ref 10.
My rule of thumb which has worked for me since I've owned it.
1. I turn it on after I turn on the rest of my system, but before the Boulder amp.
2. I turn it off 2nd, after the Boulder.
3. I turn it on about 1 hour before I venture to my listening room. I turn it off after each session. I usually listen every night or other night for about 1-3 hours.
4. I keep track of the hours with the tube counter. At 2000, start thinking or planning on replacing the tubes.
5. Give it enough head room to breathe. Do not stack.
How do you like your Ref 10 btw?
I have a similar set up.
I have the Ref 40th anniversary, similar to your Ref 10.
My rule of thumb which has worked for me since I've owned it.
1. I turn it on after I turn on the rest of my system, but before the Boulder amp.
2. I turn it off 2nd, after the Boulder.
3. I turn it on about 1 hour before I venture to my listening room. I turn it off after each session. I usually listen every night or other night for about 1-3 hours.
4. I keep track of the hours with the tube counter. At 2000, start thinking or planning on replacing the tubes.
5. Give it enough head room to breathe. Do not stack.
How do you like your Ref 10 btw?