Expected lifespan of a preamp tube?

[Baloney Balderdash]

Anyone know what the average expected lifespan of a 12AX7 preamp tube is in approximate hours of operation?

 

Also does this change depending on the kind of plate voltage they run at, like is there a notable difference in lifespan of a tube that runs at proper 300V plate voltage, and then a starved 70V plate voltage?

 

Also does it shorten a tubes life significantly if it is turned on and then off for shorter periods of time frequently compared to instead less frequently being turned on for longer periods of time (but as in same average operating time)?

 

Also does it shorten the life of a tube if is left turned on for several hours?

 

 

[itu]

1 000 - 10 000 h.

 

Whenever a tube/valve (similar to incandescent lamp) is turned on, the current spike is the harshest to the component. Less ON/OFFs is always better. If the unit has a soft start of any kind, it will most likely lengthen the lifetime of the part(s).