Twelve is not a marketing number. It is what six racks, four platforms and one coach can genuinely handle, and here is the arithmetic.
Every few months somebody asks whether we could squeeze a couple more people into the 18:45. It is a fair question — the class is usually full, there is visibly floor space, and turning people away is a strange way to run a business.
The answer is no, and the reason is arithmetic rather than principle.
The arithmetic
There are six racks and four platforms. Two people can share a rack without either of them waiting, because while one is doing a set of five the other is resting for two minutes, and those two things fit together neatly. Three people on a rack does not work: somebody is always standing about, and the person who ends up standing about is always the newest person in the group, because they are the one least willing to say “I’m in”.
Six racks, two people each, is twelve.
The other arithmetic
A coached hour has roughly forty minutes in it where a coach can be looking at somebody lift. Twelve people, forty minutes, is a bit over three minutes of attention each.
Three minutes is not much. It is enough to watch two sets properly and say one useful thing. At fourteen people it drops under three, and — this is the part that matters — it does not drop evenly. The people who get squeezed out are the quiet ones at the back, who are almost always the beginners, who are the people the attention was for.
What happens when a class is full
It stays full. We do not add a thirteenth person, we do not run a waiting list that quietly becomes a thirteenth person, and we do not open a second class in the same hour with the same coach walking between them.
If a slot is consistently full for a month we put another class on the timetable with another coach on it. That has happened four times since 2017 and it is why there is now a 20:00 on a Tuesday.
The bit that is principle after all
There is a version of this gym that runs classes of twenty-four and makes considerably more money. It would still be a decent gym. It would just be a gym where a beginner could get through an entire hour without a coach saying their name, and once that is possible, it happens most of the time, because the beginner is the person least likely to ask.
Twelve is the largest number at which that cannot happen.
