How long can preamp tubes last?


Good evening Ladies and Gents
Trying to learn! I have had a Shiit Freya + preamp for about 1 year now, and it has about 450 hours of play time, with original tubes.
Is it time to change the tubs? What tubes/brand would be recommended to purchase? 
As far as budget, I really have no idea what they cost.
Also, what does the expression" rolling the tubes" means?

Any information would be welcome.
Thank for reading.
rockanroller
I find that my CJ PV2ar preamp needs tubes about every 2 to 3 years when played 20 to 50 hours a week (average).
When that "wind" sound through my speakers gets a little loud, amp turned to zero volume,  it's time to order replacement tubes.
When the new tubes get broken-in the noise floor always drops to an acceptable levelandthe dynamics get better.
My bank account sure wishes they would last longer..... 
Depends on the voltage, the tube type and brand and how often you play it,
There was a youtube video made by Paul of PS Audio last week where he recommends changing the tubes every 6 months if not a year. The advise I have heard here suggests they usually last a very long time. Kind of different schools of thought, though I honestly don't know which is correct. May have to be your own judge. 
https://youtu.be/HdNqD_dVBR4
ok ok 1/2 a million years.. They found some with dinosaurs fossils.
Don't you guys watch the Flintstones. They used ROCK tubes..
BAT - 2000 hours then new tubes will sound amazing comparably.

Allnic - 10,000 hours

Jolida - 5000 hours

just a small sample based on personal experience