I hope this is a valid question and not too subjective:
I'm mainly a bass player, and I follow a pretty strict practice regimen on bass - a series of exercises using a metronome, that follow an organized plan based on the circle of 5ths, working on various modes and positions.
I rarely miss a day from this regimen, which takes about an hour to get through. Afterwards, I'll play through some tunes that interest me and/or reflect certain things I'm working on at the time. Sometimes I'll just play through the changes with a drum machine, sometimes I'll play with a recording.
I've been doing this for about 3 years running, after many years of on and off, disorganized playing and practicing, in groups and on my own.
It does happen sometimes, particularly lately since I'm now a 'senior citizen', that I just don't feel up to
practicing - sometimes it's a physical reason, sometimes it's a psychological reason - whatever...
When that happens, I won't do my exercises, but I will sit for an hour or two and play through a bunch of tunes of different sorts, depending again on what I'm working on and what I'm in the mood for at the time. That works because I'm always up for playing purely for enjoyment.
In the end, I never go a day without playing, to keep my hands agile and my head in the music. But, sometimes I skip my exercises. I don't feel I'm losing much by taking that "occasional day off" - maybe it even helps me to stay engaged, particularly if I'm not out and playing at the time.
Is this "OK"? Do I risk losing my edge or not advancing properly if do this more than 'once in a blue moon'?
Is playing a bunch of tunes like that as good as "practicing"? How much can I 'let it slide' regarding regimented practice?