According to Kimber's website, the full size (5 inch) and Ultra models (3 inch - dual spring) have a recoil spring life of 1500 to 2000 rds, depending on ammo, while the compact (4 inch) models have between 500 to 1000 rd spring life. It also says that if your pistol is ejecting empty brass farther than 15 feet away, it may be time for a new recoil spring. Says that 5 to 10 feet is normal....???
I run my full size pistols to at least 2000 rds since I mainly fire my own reloads that are lighter loaded for accuracy....could probably go to 2500 or higher. If I used standard full power loads all the time, I'd stick to the 2000 rd limit as a max. I don't use any +P ammo in my .45s.