Powering On/Off Tube CD Player Jolida JD-100

Would appreciate anyones help on this. I don't know if this is my imagination or just the mood I'm in that day but sometimes,
the sound from my Jolida JD-100 Tube CD player connected to my Musical Fidelity Tube X-10V3 Tube Buffer sounds different on the same CD & same levels.

What I need to know is: 1. Should I leave my Jolida tube CD player powered on all the time or is it OK to turn it complete off when I'm not using? The price of replacing tubes for usage is minimal. 2. Likewise but for a different circumstance, I leave my MF X-10V3 Tube Buffer disconnected/powered off when not using because the tube inside is 1 of only 50,000 in existence with a lifetime of around 11,000 hours. Will leaving it on, even though it will use up the tube rapidly & be costly to replace, produce better sound. as for my tubes themselves, they have alot of hours left on them, so that is not affecting variances in sound.
I'm also interested in the standby option on the Jolida...what portion of the unit is still running? Everything except the tubes?
Just a caution on the MF tube buffer...
Power it up in advance of your amp. Give it several minutes to stabilize (say 15 - I'm probably erring on the side of caution), then switch on your amp. I have read here of cases where the MF at start up gives off a signal or some sort of spike that has damaged amps turned on too quickly. I do use an MF tube buffer but mostly keep it on all the time. Somewhere on A'gon there was a discussion of expected tube life...thought it came to some 10+ yrs but I don't reccall the details and my memory is erratic.
If your X-10 V3 is on all the time, it will probably after a year and a few months be worthless. The good news is that these Tube Buffers are still available for around $250 or so.
I have an extra one. The bad news is, as I mentioned, the actual tube used, is from a finite group of 50,000 left, after that, there is no more. So the tube itself, can not be replaced. Once its connected (blue light is on), its on, whether you play music or not. You really have no idea how many hours are left on the ones sold by people on AUdiogon- they might say little use but if they were still powered on, they're being used. I basically use mine about 4-6 hours a day and then disconnect. I turn it on, with the volume of my receiver not really on because if the volume is on, it may initially make a sound.
Hershon - can't argue with turning the MF X10 V3 tube buffer off when not in use. There have been reports of amp damage based on that initial "sound" put out by the V3 so I'd recommend powering it up and allowing time to stablize in advance of turning on any downstream equipment. I've come across a claim (Polk audio forum) of 100,000 hrs for the Mu-Vista 6112 tube used in the X10. Haven't yet been able to corroborate that elsewhere. The Technical Data Sheet for the X10 found on the Musical Fidelity web site says, "This product has been designed so that it may be left on indefinitely...."