My first was a teacher and I handled it wrong. It was part time, different days every week. She didn\t pay for stats, Christmas break, March Break, PD days, or summer holidays. I held her spot for $0 through the summer, then she gave notice after being back 1 month after I told her the situation wasn't working for me and I tried to compromise.

I'd either charge a higher daily rate and save the extra for the summer and school breaks, or have her pay a holding fee (whatever makes it worth it to you) for the time she will be away.