There is a quiet snobbery about frequency, mostly self-directed, and I see it do more damage than any of the things people actually worry about in a class.
What one a week actually does
Over a year that is roughly fifty sessions. Fifty of anything is a serious amount of that thing, and I can see the difference in somebody who has done fifty when they could not do any.
Fifty is also more than most people who “practise three or four times a week” manage in a year, because that group is usually describing a good fortnight in March and a good fortnight in October.
Why the low number survives
It fits in a real life. It survives a bad week, a busy month, a visitor sleeping on your sofa and a period of work being awful, and every one of those things is going to happen.
An ambitious schedule has no slack in it. The first disruption breaks it, and the breaking is what people interpret as failure rather than as arithmetic.
The compounding bit
Skills that need repetition rather than volume do very well on one a week. Balance, coordination, breath, and the specific business of knowing where your own hips are. Those accumulate.
Strength and range move more slowly at that frequency. That is a real trade-off, and it is a trade-off, not a reason to stop.
If you want more, add carefully
Go from one to two before you consider three, and stay at two for a couple of months. Most people who jump straight to four are back at zero by the end of the season, and the drop is not gradual.
The thing worth internalising
The practice you actually do beats the practice you intended. Nobody has ever got anything from the sessions they were planning to do next month.
One class. This week. That is a practice, and anybody who tells you otherwise is selling you something. I am not.