I usually play, mostly improvisation, every day. However, the quality of musical creation is not proportional to the time spent on it beyond a certain minimum. In fact, I would be confident in asserting that other activities and influences in life seem to help creation rather than hinder it. Now no doubt performance is an entirely different kettle of fish, but as I have no desire to perform I am not concerned with working very hard to get my limited repertoire of set pieces up to the last 5% of perfection.
Having a lot of time is no guarantee that I shall produce things of greater musical significance. Therefore becoming possessive and precious about time is psychologically negative for me. No doubt I shall spend much more time at it and maybe even write more things out when I retire or work less, but I do not kid myself that the quality of my music depends on time. Some of the best music I have created has emerged during abominably restricted musical activity.
It's a bit like saying that because one man can mow a lawn in half an hour, a million men can therefore mow it in a fraction of a second.