Just how much do you spend on tubes per year on average ?

@inna running power tubes beyond 2000 hrs is very risky in my opinion. I had a power tube failure in Rogue ST100 amp and it took out several parts on that channel. Was repaired by Rogue. I sold the amp shortly after. 

With VAC the repairs will be costly. Up to you of course but I would swap tubes at 2000hrs and box them up for spares. 
 

I also had NOS small signal tubes go bad in preamps but they usually fail more gracefully than the power tubes. They became microphonic, were farting and making other weird noises. All tubes were purchased new from upscale audio or tube depot. Several failed in a course of 5-6 months. 

Highly dependent on how hard the circuit is driving the tubes. 
If you have a good supply of tubes you’ll be fine but I wouldn’t push the hours envelope. 

@audphile1 How do you keep track of hours?  

@sls883 

https://elusivedisc.com/stylustimer-turntable-odometer/
 

or use average based on listening habits. 
Audio Research and some other manufactures started adding hours counters as a feature on their preamps

OP

Highly dependent on the system synergy and how hard the Amps are on the tubes. I have tube rolled since only the pandemic, and I must have hit under 2K for 5 years? not bad. But note, I only buy NOS. and I have an 845 Power Amp. 

So just to be clear, I am not referring to Tube maintenance (tube replacement) but rather Tube tuning / rolling. The good thing is that you will eventually find what you want and settle for that brand, make and model. 

then if you gear is easy on the tubes, (I have the LTA Microzotl)  that can last for years. So, my opinion is to Tube roll and find what you're looking for and then settle on the tubes. just get replacements as budget allows

@audphile1 thank you.