It depends.....
How often you shoot, how many rounds you shoot, and how fast you shoot it.
With newer steels in the barrels, and better cleaning materials and techniques, barrel life is much better than it used to be.
Most of the 7mmRUM rifles (and 7mmWby) are "hunting" rifles, hence, they are shot to sight in (and/or develope handloads..) and then are carried much, and shot little...
So, barrel wear doesn't matter much.
A former business aquaintance has a 7mmWby MkV. It's 15yrs old, has taken a dozen elk, and numerous deer. Between him and his two sons, it's probably fired 250rds in that time. He simply buys 5boxes of ammo (Weatherby w/Hornady bullets)at a time and replaces them when they run out..... And, it wears a Ziess scope that was once sighted in has not been "touched" since original sight-in. This is probably typical of this type rifle......
A former co-workers best friend has a large plantation/farm in mid-south Georgia. He grows pecan trees and soy-beans, cotton, and corn... So, he also has lot's of big deer. (bodywise....). He's got a Winchester M70 in .264winmag that he's used for over 35years. He "bought out" a large supply of 100gr and 140gr factory loads when a hardware/gun shop "clearanced" out their supply of .264 ammo back in the early '70's. He only recently started reloading for it. He estimates he's got ~800rds through the barrel from shooting crows with the 100gr's and 140gr's for deer. He says it will still shoot 3-shot 1.5" groups which is what it's always done..... He's now near 60yrs old and will not buy another rifle, so he says... (He did buy a .22-250 for shooting crows and p-dogs).
So, even the "worst" barrel burner ever, has given a lifetime of service under "reasonable" use.... (he's also taken several elk with it in Colorado...).
fwiw; I recently bought a circa early '70's Interarms MkX in .270. From the exterior of the rifle, it has seen extensive hunting use (much like mine in .30/06 I killed my first deer with in 1976....). From the appearance of the bore, it has had less than 200rds through the bore, and shoots sub-1/2moa with 140gr bullets over 58.5gr of RL22.....and 3/4moa w/130gr bullets...
I suspect that most 7mmWby and 7mmRUM's will see similar service....when used by the average hunter using factory ammo......
I've got a .300RUM and a .257wby. I don't see me "shooting" one out in my life-time.... I've got too many other guns competing for my "attention"....