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

Showing 1 response by rockanroller

Thank you ALL for the great inputs!
Did learn a lot and sound advice was given!(no pun intended)
Much appreciated.
Rockanroller