Out of curiosity... Do you make a contract just for wedding cakes or all cakes?
All cakes. You never know what might come up. Also, the contract reinforces the fact to yourself and to others that you are a professional.
A sales receipt is a contract. Because my cakes are prepaid in full on my e-commerce site, all are a contract. In the cart, the exact dessert with any additional information is stated, all information on the client and delivery is found, and the trems and conditions must be checked. Finally, the requirement of any valid contract, consideration, in our case, money, is exchanged. This is a complete contract.
You don't need an e-commerce site to do this, but a complete receipt makes sure all understand the termsof the transaction.
Every cake...The worst problems I've ever encountered were with birthday cake clients.