How long you must wait before you can move in depends on the terms of your purchase agreement. In most cases, unless there’s a specific clause in the contract, you can move in when the transaction has been completed with your mortgage company. As soon as you sign all the documentation, it’s yours.However, sellers may ask for more time before moving out. If so, this is negotiated in the purchase agreement. If you agree to give them more time, you have to abide by the contract. In exchange, the seller usually pays rent for the amount of time they remain in the home after closing.