Leave for piano teachers

Today just told 3 of my private students that becoz 52 weeks a year/4 weeks (per mth)=13 months, im entitled to 1 month=4 lessons of holidays on top of the public holidays.

Guess only one felt a bit resistant coz they were going holidays and missing 3 weeks of lessons including 1 week which lands on 1st Jan (public holiday), but i'm still charging a month.

Previously i find it very difficult to tell them, coz by right wat u teach is wat u learn. But then, all employees in companies including my current music school have School holidays on Top of public holidays. Moreover my ex-piano teacher also implemented holidays in Dec but we still pay fees, can't remember if it was 2 or 4 weeks though. But it's unfair that private teachers have no leave, since everyone else have...so i have to push it. If not it's like working non stop when everyone else have leave...

Anyone knows wat the market practice is like?