In addition to documenting the business terms, legal advice for business contracts ranging from software licenses to real estate contracts and leases is a preventive law technique designed to clarify the business transaction, reduce litigation risks and reduce aggregate legal costs. Although valid oral agreements are possible, their potential for disputes makes them highly inadvisable. In some areas of law, an oral agreement may not be enforced. These areas more commonly encountered by business owners include sales of goods for $500 or more, sales of interests in real estate, and copyright assignments and exclusive licenses. Since a contract cannot cost-effectively address all potential disputes, frequently business contracts will contain alternative dispute resolution provisions, such as arbitration, in an effort to avoid more costly litigation.