I agree that a Ruger "DA Six" series can still be used as daily carry or any other reasonable purpose, assuming it's in good shape as the vast majority are.
Springs are still available, that's really the only "normal wear" part on it.
I also agree that they should be fed milder forms of 125gr 357Mag at most - stuff like the Cor-Bon DPX 125 is loaded mild and won't hurt the gun. Anything heavier in power should also be heavier in bullet weight.
I am particularly fond of the Speed Six 2.75" and consider it among the finest factory street-fighter revolvers ever made.