With not having a contract (which I think is a silly idea for both provider and parent!), you can give whatever notice you like but to be fair to your current provider, I think 2-4 weeks is ideal. I ask for a month. This usually gives me enough notice to find another family. However, if a family knew they were leaving and could give me more than that, I'd be so appreciative! It is stressful when a family leaves as that's a chunk of our income instantly gone and the longer we have to try and fill the space, the better! Good on you for being considerate and not just leaving because you technically can without a contract.