It is best to contact a lawyer before you sign an offer to purchase, whether you are buying or selling. Once you sign the contract, you are bound by it. If you have any questions or are unclear about the meaning of any terms of the contract, a lawyer can explain them to you. Once you sign the contract, you are bound by its terms. Any disagreements as to what the terms are understood to mean can lead to delays at best and costly lawsuits at worst.