What happens if I do not have a written contract?

What happens will in large part depend on the facts and circumstances of your specific situation. What can happen is that a court may not recognize your agreement as being an enforceable contract. If you do not have your agreement in writing, then you will have to rely on corroborating evidence to prove that you have a contract.  Another possibility is that you may not obtain all the benefits of your bargain.  In other words, the terms of your agreement may not be clear enough to be enforceable.  Or, you may find that your memory differs from the other party’s when it comes to crucial points of your agreement.