Contracts are legally enforceable agreements between two or more parties who agree to a mutual exchange of obligations. In most circumstances it is possible to create a legally enforceable agreement orally, however, some common business contracts may never be formed orally, including:

• Contracts which cannot be performed within one year;
• Contracts for the sale of goods involving a purchase price of $500 or more; and
• Contracts in which one party becomes a surety for another party's obligations.

The trouble with oral contracts and handshake agreements show up when the parties disagree upon the substance of the agreement, when a party finds out the actual cost of performing his or her obligation is more costly than originally anticipated, or when the parties discover that they were on completely different pages when forming the oral agreement.

While theoretically enforceable in court, actually enforcing an oral contract or handshake agreement is very difficult because proving the existence of the contract, not to mention the terms and conditions of what exactly was contractually agreed to, is very difficult absent tangible evidentiary proof.

Written contracts, signed by the party against whom enforcement is sought, are not only infinitely easier to enforce in court, but when well written are also valuable tools in avoiding mistakes, ambiguities, and other common sources of contractual dispute.