Originally Posted by Lucy:
For an entire week? As a parent, I think I would want as much notice as possible. Four weeks just doesn't sound like much time for them to find alternate care, or end up having to take the week off work. Are you actually only planning your vacation four weeks ahead of time? If you plan it earlier than that, I would tell them AS SOON as you know the dates.
What I do is plan at the beginning of the year when all my days off will be. Then I type up a full-year calendar and give it to them by about the 2nd week of January. That's when most places of business have you sign up for your vacations, so I want them to know when Daycare is closed so that they can take their vacation days to correspond with mine. I like to be as courteous about time off as humanly possible.
Not saying this is the only right way to do it, just saying what I personally like to do. 
my contract tells parents they should ALLOWS have backup care plan in place at ALL times. It should be no problem (and never has been) for a parent to implement their back up plan with four weeks notice. If they do not have anyone to help out, I have a list of providers that do backup care. There is no reason why a parent should not have some sort of plan in place! If they absolutely have no way to have any plan B, they need to go to a facility that does the planning for them.