As a parent I appreciate the contract. Like AmandaKDT says, it adds professionalism. It is comforting to have the rules spelled out for all parties and it addresses sticky issues (sick kids, vacations) before they they occur.

As for hours, I wuold match the typical business in your area. If office...do 7am - 5:30 (gives parents enough time to drop off before and pick up after work). If manufacturing..you can look into shift, drop ins, flex time etc. BUT...I counsel you to leave some time for yourself. A burnt out caregiver will end up needing care, not providing it.

Hope this helps