Life Expectancy of a NOS 5751 Vacuum Tube


Just curious, can anybody shed a light on how long a typical NOS 5751 vacuum tube last assuming normal use (2-4 hours a day)? I found the same info for the 12AX7 (same family or comparable to a 5751 but with higher gain)but not for the 5751. Your input is greatly appreciated.

Life expectancy sould be about the same as the 12AX7 in the same application.
If anything, it may be a tiny bit more I'd think. The gain on the 5751 is a bit lower, yes ?

But I happen to love 'em, using NOS 5751's now instead of 12AX7's.....
Thanks "Newbee" and " Chams uk". I too bought some 5751 lately (Sylvania Gold brand 3 Mica Black Plate Goldpins, RCA Black Plate 3 Mica, GE Black Plate 3 mica, Raytheon, Tungsol etc.)and prefer to use it , than the 12AX7's, in my application.