The operative word in the terms gunfight, knife fight, fistfight, etc is ... '"fight". You're in some sort of suddenly dynamic confrontation.
Age and physical condition (disabilities, infirmities, etc) will always be a consideration, for all of us, as well as being on the receiving end of any force that causes us new injury. Learn and know yourself and your limitations. (Talk to your doctor.)
While I'm closing in on having seen my 5th decade as a martial artist (reached next year), I've also had an interest in firearms since my dad first introduced them to me as a youngster, and then I received some various specific training during the 26 years I served as a LE firearms instructor.
All of that has helped me to come to realize that for everything I've come to know, there's always much more I don't know. In the long run, though, coming to know yourself (and your limits) is more useful than trying to keep up with every single advance in gear and hardware ... because
you're still going to be the gear
user,
or someone else may be using that gear
against you.
It wasn't until I'd been serving as a firearms instructor for about 5 years that I started to think more seriously about merging more of my martial arts background (about 25 years, by that point) with my
personal firearms training. (As an agency instructor, especially if you're just a junior instructor in a training unit, you're constrained by policy to teach what's approved and mandated, as those training methods and records are available to subpoena and detailed explanation in court. You use the sheet music you're given.)
That just happened to be a point in my martial arts pursuit where I was building up to a surprising epiphany in seeing more deeply into the arts I'd thought I already "knew" somewhat well. In my case, it was having taken on a private student who ended up triggering the circumstances that involved my epiphany. It made my 25 years of involvement in some arts seem as though I'd been treading water. Suddenly, everything began to gel in new ways, and reveal connections I'd either not previously seen, or hadn't seen into deeply enough. This included adapting more of my arts into my firearms training (movement, balance, postural shifts, fluidity, awareness, etc). It's still (unsurprisingly) ongoing to today.
Among many of the recorded quotes of Miyamoto Musashi are some that keep anchoring and grounding us:
You can only fight the way you practice.
A bullet from a gun does not make a distinction between practice and combat. You are training to be one and the same in your life.
If you learn indoor techniques, you will think narrowly and forget the true Way. Thus you will have difficulty in actual encounters.
They speak of "This Dojo" and "That Dojo". They are looking for profit.
One of my favorites:
You should not have a favorite weapon. To become over-familiar with one weapon is as much a fault as not knowing it sufficiently well.
Even if you don't own (or want to own) a copy of The Book of Five Rings, there are many online sources where you can find a variety of his quotes. One of many is this one:
https://www.idlehearts.com/authors/miyamoto-musashi-quotes
If you're going to get involved with a martial art/discipline, keep in mind that injuries are counter-productive to training ... and especially as you enter middle age, and then senior age, etc. If your training partner or instructor is still enjoying the invincibility and hubris of youthful vigor, be cautious to avoid finding yourself on the receiving end of any enthusiastically applied force that's done out of ignorance, or even the sheer exuberance of youth, unfettered by concern for potential injury.
Nowadays, one of the goals of my continued physical training is to not only try and stave off the inevitable ravages of normal aging, but to complete training sessions without experiencing new injury, or an exacerbation of an old injury.
Ditto during my shooting sessions, when I can schedule some time at my old agency's private range. Granted, now that I've hung up my instructor's hat and belt, I'm no longer working a few sessions each month - more like a few sessions each year - but that doesn't mean the quality of the sessions has to suffer. If anything, nowadays I expect
more out of each and every range session, because I'm no longer having to spread my time and attention among all of the other shooters. Quality over quantity can have merit.