There’s no upper limit to how much you should repeat yourself.
The old oratorial advice is “Tell them what you’re going tell them, tell them, then tell them what you told them.” I assert that that’s not nearly enough times telling them.
Tell them, tell them again, tell them again. Remind them what you told them. Tell them again (a different way).
Repeat yourself. And then repeat yourself some more.
I’ve got four or five expressions I have polished to simple and clear sentences, and I repeat them very often – often enough for my students to memorize them or start tally sheets.
They say that the people you lead won’t remember what you said, they’ll remember how you made them feel. Well, if you repeat a few things enough times, they might remember those things, too.