A method for limiting use of an analyte sensor to a predetermined time period, the method comprising: providing a key associated with the analyte sensor, wherein the key comprises sensor duration and is configured to control an amount of time over which information is obtained from the analyte sensor, wherein the analyte sensor is a transcutaneous glucose sensor, wherein the sensor is operatively connected to a receiver, wherein the receiver is configured to display sensor data, wherein the sensor duration is enforced by: a. when the sensor duration has been met, the receiver is configured to disable display of the sensor data, yet the sensor continues to collect and the receiver continues to store the data after displaying of the sensor datahas been disabled; and/or b. a sensor system comprising the sensor, a housing adapted for placement adjacent to the host's skin and for supporting the sensor upon insertion through the skin, and an electronics unit operably connected to the housing, the sensor system configured to destroy the sensor when the electronics unit is removed; and/or c. the receiver is programmed to algorithmically identify a new sensor insertion by looking for change in signal characteristic and if a user has not inserted a new sensor, then the continued use of an expired sensor is detected and is used to trigger a shut down of the sensor and/or the receiver. providing a key associated with the analyte sensor, wherein the key comprises sensor duration and is configured to control an amount of time over which information is obtained from the analyte sensor, wherein the analyte sensor is a transcutaneous glucose sensor, wherein the sensor is operatively connected to a receiver, wherein the receiver is configured to display sensor data, wherein the sensor duration is enforced by: a. when the sensor duration has been met, the receiver is configured to disable display of the sensor data, yet the sensor continues to collect and the receiver continues to store the data after displaying of the sensor datahas been disabled; and/or b. a sensor system comprising the sensor, a housing adapted for placement adjacent to the host's skin and for supporting the sensor upon insertion through the skin, and an electronics unit operably connected to the housing, the sensor system configured to destroy the sensor when the electronics unit is removed; and/or c. the receiver is programmed to algorithmically identify a new sensor insertion by looking for change in signal characteristic and if a user has not inserted a new sensor, then the continued use of an expired sensor is detected and is used to trigger a shut down of the sensor and/or the receiver. a. when the sensor duration has been met, the receiver is configured to disable display of the sensor data, yet the sensor continues to collect and the receiver continues to store the data after displaying of the sensor datahas been disabled; and/or b. a sensor system comprising the sensor, a housing adapted for placement adjacent to the host's skin and for supporting the sensor upon insertion through the skin, and an electronics unit operably connected to the housing, the sensor system configured to destroy the sensor when the electronics unit is removed; and/or c. the receiver is programmed to algorithmically identify a new sensor insertion by looking for change in signal characteristic and if a user has not inserted a new sensor, then the continued use of an expired sensor is detected and is used to trigger a shut down of the sensor and/or the receiver.