The length of an option agreement, known as the option period, is negotiated between the buyer and seller and can vary widely depending on the asset in question and the needs of the parties. It could be as short as a few days or as long as several years. Commonly, option periods may last from three months to a year in financial markets, while real estate option agreements might have longer periods to allow for due diligence and financing arrangements. The specific duration should be clearly stated in the agreement to avoid any confusion.