I have two like this, and I regret not being firmer with it when they started. They were my first two families, and I wanted to be accommodating. One is here anywhere from 2-5 days a week, but the other is here 1-3 days a week - but I've kept a full time spot open for both. I've decided to just take on another child and treat the 1-3 day a week kid like an extra (it still wouldn't put me over my numbers).