The hardest part of planning a rehearsal is all the things you don’t know.
You don’t know who will be absent, but you also don’t know what unexpected things will happen, what musical discoveries will be made, what setbacks will happen. What notes you’ll have to re-teach because they didn’t stick. What jokes will surface.
Dealing with that requires two things.
First, long-term mindset. I don’t worry too much about meeting today’s goals, as long as we are making the right amount of progress toward’s this month’s goals. Everything balances out over multiple rehearsals, with the right planning and attitude.
Second, flexible perspective. As I’m rehearsing, I’m thinking about the next minute, the next 5 minutes, the next hour, and next week. I’m reacting in the moment and revising plans based on what’s happening. A strictly followed rehearsal plan does not really serve the actual humans in the room. Maintaining flexible perspective does. The plan exists, and the plan is revised moment to moment.