Its good to hear the the PF-9 holds up to a good amount of use. I assume if you use it a lot you are a very effective shooter if the need to use the gun ever happens.
I shoot my kel-tecs on occasion but carry them often. Use my steel pistols at the range for target practice and just for fun. So I guess I would not be as effective if ever in a gun battle, but I am sure I could hold my own in a strictly defensive shooting. Usually those are over in seconds and few rounds are fired.
Simply shooting a lot does not, unfortunately, translate into effective defensive shooting. Just depends on what "kind" of practice you do. To be effective, such practice should be as close to a "real world" situation as possible-that is, shooting from different distances, positions, targets, drawing and firing, point shooting, shooting while moving, using cover while shooting, practicing clearing jams, and so on, along with a lot of mental practice on "what if" situations.
You don't have to use your PF-9 for this, although you should use it enough to be completely comfortable with it at all times, including automatic responses to jams, etc (which can happen with any firearm, regardless of type, size, caliber, or cost) In fact, it can be somewhat counter-productive beyond this, since the more wear and tear you put on a given pistol, the more likely it becomes for something to break at a critical moment. The trick is to use it enough to ensure it runs, and to build and maintain your skill with that particular weapon, but not to create undue wear on a carry piece. They are, after all, very lightly built (intentionally so, as to keep weight and size to a minimum for the caliber) and not robustly built range or target pistols. JMO
Jim R