In some embodiments, a pressure-sensitive mat and a monitoring device are part of a pressure relief compliance system. The pressure-sensitive mat is placed between a seat cushion and a chair. When a user sits on the cushion, the system will monitor the time the person spends applying pressure and will notify a user with an alarm or by other means when the preset sitting limit is reached. Also a novel method for measuring and adjusting the amount time spent applying and releasing pressure. In some embodiments, rather than simply measure time spent applying pressure, the system will allow the user to “buy back” sit time when the user releases pressure. The rate at which the system will credit the user with a “buy back” of sitting time may in some embodiments be directly proportional to the amount of time the user spends performing a pressure release.