As you well know, now more than ever, you are also running a business. Call them within 24 hours. They will appreciate the follow up, because 'good service' is not what they usually get. This could lead to many referrals, and that condominium at the beach. Private school or day care center.
New students are customers.
Do not wait until a concern becomes a problem, as they probably have told many people about it by that time. You operate a complicated business, and you can anticipate that many customers will have initial concerns which are important to them, and easy to resolve if you know about it. Considering that you are providing an important service to them, it will help them feel better about you, and their decision to use you, if you do a prompt 'satisfaction survey'. Call within a week soliciting any issue they want to talk about, heading off problems, and maybe generating references. But now you want to capitalize on this great new marketing tool, and recover the expense of the folks with the propellers on their beanies that got you up there.