Do what is best for you and your family. Don't worry about your clients being able to find alternate care for their children. There are lots of excellent caregivers out here, and I'm sure that they will be able to find a suitable replacement quite quickly. I would base your decision about how much notice to provide on your own economic situation - how well can you function without your current income ? If losing your income will be a hardship for you, I think one month's notice is more than fair. (Yes, you can expect your families to fly the coop as soon as you break the news that you will be closing) Good luck in your return to the (adult) workforce !