This is key. You need to decide what services you will offer at what price and let potential clients decide if it works for them. The biggest mistake I see new barns making is attempting to be a barn for everyone.
Especially if you intend to have hired staff to do the work, you need to limit available services or risk the time to do the work ballooning. That will either increase your payroll costs, or increase staff turnover as the work exceeds the paid time. Something that “just takes a minute” actually takes longer to set up, perform, and clean up, and then needs to be multiplied by 30. A genuinely five minute task costs two and a half hours in labour each month (double if it’s twice a day).
As a kid I learned to ride at a city owned barn that ran six eight week sessions per year. I paid each session before it started, and there were no make up lessons. When I was going to miss two or more lessons I didn’t ride during that session. That sucked. If I’d been able to make up one of the eight lessons within the same eight weeks then I would have paid for the lessons. Something to consider.