My dept issued 5904 for several years. They're very well made, they'll shoot a lot better than most shooters, and very reliable. It's highly unlikely you'll wear one out. One of our range guys decided to wear out a 5904 by shooting it to death using our issued W-W 115 JHP+P+ ammo. At around 50,000 rds he replaced the barrel because he'd shot nearly all the rifling out of the original. Some time along the way he replaced the springs but I forget the rd count. When he retired he had about 85,000 rds thru it. He bought that same pistol and as of a couple of months ago was still shooting it. Knowing how much he shoots he has to have over 100,000 rds thru that same gun and other than some holster wear it looks pretty good.
How likely will it be that you'll run 100,000 rds of +P+ ammo or any kind of ammo? Consider the cost involved. If you can find a deal on that ammo at $20 a box you'd spend $40,000 on the ammo. A $400 gun is pretty cheap compared to the ammo prices. If you would buy $40,000 worth of ammo figure how long it will take you to shoot it all if every Saturday of every week during the entire year without fail you fired 50 rds. It would take you 38 years to fire all the ammo.