Best Way To Maximize Preamp Tube Life?

I done 24h a day on in 2 years tubes are going bad. So now I set it off when not in use. Tubes even good pre ones are getting expensive too.
Befor a listening session of 3 or 4 hours I set the pre amp on one hour befor then it's getting pretty good sounding. 

I really enjoy reading through this kind of discussion. I am new to tube preamp/amp ownership and I honestly had no good information on how to approach the maintenance. I have been turning my system on about 15-20 minutes before I start playing music just to let it warm up. The preamp and amp are usually on for 3-4 hours on average. Some days they will stay on 8-10 if the weather is bad and I am just chilling in the house. 

I definitely need to buy some spare tubes.

Cheers!

Best way to extend tube life is probably going to SS…
I should replace those 20 year old tubes in the preamp. But it sounds pretty good the way it is.

I'd never leave any tube equipment on 24/7. Some have standby mode, in which only heaters are lit, some also have soft start circuits, both minimize wear. The rest you're choosing between wear and tear from being used 24/7 or same from inrush current, voltage. So, sort of depends on how often and how long you listen to music. Daily listening, may as well leave on. Still, I don't like leaving tube equipment on unattended, too many bad things can happen. Preamps slightly less worrisome here, still?

I'd never leave any amp on 24/7, regardless of how often listening. I've always thought ss best for multiple daily listening sessions.
I subject the expensive tubes I prefer to the lightest wear possible, they are not simply disposable items to me.  I'm once a week, long term listening session guy.

I have purchased a spare set of tubes for all my components. In the unlikely need to trouble shoot they are there. Also, when the 3,000 hours are up. Sure, they may last longer.