[Creeper]

I doubt there's a substantial quality difference between the two brands springs. I think that Kimber addresses it to cover their bases, while Colt makes an assumption that the user knows this. It's a WAG on my part... but that's how I perceive Colt and Kimber as companies.

This is what Wolff Springs has to say about it:

4. How often should I change my springs?
The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increased ejection distance, improper ejection and/or breeching, lighter hammer indents on primers, misfires, poor cartridge feeding from magazines, frequent jams, stove pipes and other malfunctions are all possible indications of fatigued springs or improper springs.

Springs such as magazine springs, striker springs and recoil springs are subjected to higher stress levels and will require more frequent replacement than other lower stressed springs such as firing pin springs and hammer springs.

Wolff springs are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. Some recoil springs in compact pistols, especially where dual springs are used or are replaced by a single spring may require changing after 500 - 1500 rounds. Springs that become rusty, bent or otherwise damaged should always be replaced. Again, changes you observe in your firearm's performance are the best indicators that a change is needed.

Cheers,
C