In terms of live fire, I do at least a once per month FOCUSED draw from leather, smooth presentation drill(s) involving 50-100 rounds at various "combat ranges". I practice various drills. to determine what I am satisfied with and what I feel could use additional improvement.
That's a minimum. Depends on weather and whatever else, but once/month at a minimum. Maybe more, occasionally a tad less. Why? Because my life may depend on it and I don't want to botch the job when the time comes. That's what I feel I can afford to commit to and what I feel meets the standard of good faith to my committment to myself.
This does not include dry fire drills. Dry fire is about once a week, and, again, these are FOCUSED and disciplined drills and not simply farting around. I like to practice for maybe 10 minutes/week for one session in this arena. About. Not including the occasional not quite fully disciplined farting around dry fire I do to practice trigger control, grip, stance, etc.
Finally, I try to get professional help about once a year thru a class of some sort to insure that I don't overrate where I think I may be in my proficiency.