I am of two minds on repeating yourself in rehearsal.
On the one hand: repeat yourself until the message sinks in. My students shout back at me some of my rules of music-making with the slightest prompting:
“We’re dragging. Why not try…” “Physicalize the beat!”
“The only way to memorize is?” “Repetition!”
“How do you pronounce December 25th?” “Rhymes with Swiss Miss!”
and so on…
Repetition of important musical ideas that can be applied in lots of contexts is the best way to make sure they sink in; if they’re important, repeat.
On the other hand:
Repeating housekeeping “business” details – performance schedules, planning details, attire, etc. – is risky. If I repeat myself too often, my students learn that they don’t need to listen to me when I tell them this kind of information, because they know they’ll hear it again.
In this case, repetition makes is harder for them to absorb information.
If my students know they’ll hear important schedule and planning information once, maybe twice, they will learn to pay attention when we talk business. (They might learn the hard way, by accidentally double scheduling themselves and missing something important. That’s fine – it’s part of learning.)
Repeat yourself. Don’t repeat yourself. It all depends on context.