Define contact hours
Tell parents when you respond (e.g. weekdays 9–6). Messages outside that wait — this prevents burnout.
Scope is not unlimited
You teach the agreed subject and level. Extra subjects, unlimited marking, or 24/7 chat are scope creep — price or decline them.
Cancellation policy protects both sides
Written notice rules are a boundary, not rudeness. They protect your income and teach respect for your time.
Saying no professionally
"I do not have capacity" or "that is outside what we agreed" preserves the relationship better than slow resentment.