I charge a 2 week deposit, which is deducted from the last 2 weeks of care.
I do monthly fee schedules detailing how many days they are scheduled for, and how much perday.
I take 6 months of post dated cheques at a time, and payment is all on the 1st, or divided btwn the 1st&15th, so I am in control of the cheques, and always have them in advance.