After 25 years in the camera repair business I still think Energizer S76 and 357 are the best. Both are silver oxide chemistry. Of course, I've been retired for 22 years, but I don't think much has changed in the battery world. The Lithium batteries are too new for me to have an opinion.
Watch out if you go to Amazon. It appears from the feedback that several of the sellers are dealing in outdated batteries. Cameramonkey's recolletions are correct as to interchangeability.
One of the real/ly nice things about the p938 is that you can rack the slide with the safety on. This adds to my feeling of comfort when I'm clearing it.
Caliber not important, size not important, condition not important. All that I really need is the frame assembly (firing mechanism) and the takedown lever. All that is important is that the firing mech work and the price.
Ahrends grips isn't close, but they are good and will make grips from your wood. Grip making is their only business. I've got one set of theirs and have been very pleased.
The P250 trigger is the closest one to the Sig DAK trigger that I have seen. I felt it was much better than the Glock. One of my grandsons conned me out of mine. If I can ever find a deal, I'll get another.
I've been using the Pro Ears Gold (now called Pro Mag Gold) for for a lot of years. They are not cheap, but I wanted to save what hearing I have left after shooting for a lot of years with inadequate or no ear protection. Just about every part of them is replaceable if you need to.
Not as dramatic but similar is the Hawaiian island of Kahoolawe. We've used it as a gunnery, boming and torpedo target for many years. It's loaded with unexploded ordinance.