What fees to charge. Term time only, minimum hours, holiday pay???

I am SO confused. I am about to register but i'm so confused on what fees to charge. What fees to charge parents for term time only (if you do this) how do you cover for your holiday pay.
Do you charge parents for school holidays if they don't need their child looked after. Do you charge different fees depending on how many days they use you for, & do anyone charge more for term time only?
If you charge half price retainer for holidays does that mean you cant take any holiday only children?
Head mashed!!!

I charge a flat daily rate for those not in full time education - can't be bothered with half days etc and we only have three little ones spaces. Before and after school I do per hour of a minimum of two hours. Teachers, LSAs and Students who want term time only have to pay a half fee retainer in the hols.

For all day children I charge an hourly rate, no one attends for less than 9 hours a day. They all seem to be on different rates as my 3&half yr old, who has been with me from 6 mths old hasnt had one rise, but a new toddler is charged higher and their rate propably won't rise either. This doesn't bother me because if/when they become before/after school care the hourly rate rises a lot. Term time only children, all day & before/after school care, all pay half during the holidays but I'm finding that parents do sometimes want childcare and then will pay the other half for the day their child attends. So I'm always aware I need to have a space for them when booking in children during the holidays.