Location, soil, climate, expectations, maintenance, projects.
52 weeks per year.
Less X days/weeks/months for poor/inappropriate weather (snow, frost, storms, heavy rain/flooding, heat wave etc)
Less Y for days/weeks maintenance time (spiking, dressing etc etc)
Less Z days/weeks/months for maintenance projects (all sorts)
Less other
What’s left?
And what’s left may not be optimal, and optimal is subjective.
Good question though.
Atb