An option is an agreement whereby the person with the benefit of the option has the right, exclusively, to purchase a property, usually at a price that has been agreed or that is to be determined by way of a formula. Options can be extremely useful, for example because a developer wishes to secure land for the future, but without incurring significant up front expenses, as usually a (relatively) small fee will be paid to secure the option. Prior to 6 April 2010 (the commencement date of the Perpetuities and Accumulations Act 2009 (PAA 2009)), an option was valid only for a period of 21 years, by virtue of section 9(2) of the Perpetuities