As a current in home provider, my clients do pay for my vacation time however it is only 7 days per year and generally during the summer. I also take paid holidays and sick days
Did she tell you how much time she would take off when she started? State it in her contract? If not, I would bring it up and see how much more she plans on taking. Many companies offer benefits. Paid time off, vacation, sick days, insurance etc. As a provider, you have to give yourself these things. Some people think of it as unfair because they look at it as another woman, friend etc. asking for money when they're not doing anything. You have to look at it as a company. It's the same for parents who are frustrated when they take vacation and they still have to pay. You are paying for your childs slot not the time there. It's makes the income reliable for the provider. Just because you only watch your cable 15 days a month doesn't mean you only have to pay for 15 days.
Hope that helps!