I tell people 4-6 weeks is longest I hold. I take a 2 week deposit regardless and hold it as their last 2 weeks care. When I moved and set my daycare up again I purposly wanted a gradual build up of children so when someone enquired in the April for an October start I said it was fine but on the condition that she paided a 50% retainer to hold the spot. I explained why and that I get enquiries constantly and could very well get an enquiry tomorrow for a start the following week and if I held it for her I would lose a substantial amount of income. She paid the retainer becasue she wanted her child to come to me enough that it was worth it. In my town there is a real shortage of daycare so it is a little easier to make these kind of requests but generally this isn't something I do, I just tend to ask people to call back 4-6 weeks before returning to work.