I have two. The 'K-9' has factory tritium sights and is my 'bedroom' and practice gun. The other is a 'P-9' with AO Big Dot Tritium sights. The tupperware P-9 gets out much more than its steel brother. Both share the same mags, holster, trigger stroke, presentation drills, etc.
Both are reliable with bargain basement ball, Gold Dot, Cor-Bon, and Glassers.
I make a habit of changing the recoil springs every time I change the oil in my wife's car. Thats about every 90 days. I know it sounds silly, but it makes it easiser for me to remember to change the durn things if I key the memory synapses that way. Kinda like remembering to change the filter on the ac/furnace every time I get a bill from the Texas Utility Company.
Whatever works for you.
salty.