CGM sensor wear times are set by manufacturers based on FDA approval data: 10 days for Dexcom G7, 14-15 days for FreeStyle Libre 3 and Stelo. Many users ask whether sensors can be extended beyond these periods. Here is the honest answer.
Why Sensors Have Limited Wear Times
The enzyme coating on the sensor filament degrades over time and with glucose exposure. Accuracy decreases progressively after the approved wear period — the rate varies by sensor and individual. Manufacturers establish cutoffs where they can guarantee accuracy within their MARD specifications.
Dexcom G7: 10 Days + 12-Hour Grace Period
The G7 includes a 12-hour grace period that is officially supported. After 10 days, the sensor continues to transmit with the grace period notification. This is built-in by Dexcom and does not void any warranty. Beyond the grace period, the sensor shuts off automatically.
FreeStyle Libre 3: 14 Days
The Libre 3 terminates at exactly 14 days — there is no grace period or unofficial extension. The sensor physically stops transmitting at day 14, enforced by the sensor hardware.
xDrip+ and Sensor Restarts (Older Models)
Some older CGM sensors (Libre 1, older Dexcom models) could be “restarted” using xDrip+ or third-party hardware to extend wear beyond the approved period. This practice:
- Is not officially supported and voids any warranty claims
- Results in decreased accuracy (the sensor filament is degraded)
- Is not possible on Libre 3 or Dexcom G7 due to hardware enforcement
The Better Approach: Optimize Each Sensor
Instead of extending sensors, focus on maximizing accuracy and adhesion within the approved period: proper site preparation, adhesive overlays, avoiding compression, and confirming suspicious readings with a fingerstick. A well-managed sensor within its approved period is more reliable than an extended sensor of questionable accuracy.
Cost Savings Without Extension
The most cost-effective legitimate options: manufacturer savings programs (Dexcom Access Program, FreeStyle Promise), using the full wear period consistently, and checking whether your insurance covers sensors as DME.