We have 30 buns. We offer permanent sanctuary places, so we like rabbits to have 24hr access to a run attached to their hutch if possible. This isn't always possible in winter because some of our more vulnerable rabbits have to go into the garage or house during the colder months.
We also have some runs on the lawn, but I can only put the rabbits out at weekends, or sometimes evenings during the summer. We have foxes around here, so I can't have the rabbits out on the lawn unless I'm watching them.
Being a sanctuary, we like all our rabbits to live in a pair or group because they are permanent residents, so we require fewer runs than a rescue who rehomes mainly single rabbits