CGMs are disposable, for example the Dexcom sensor that is replaced every 10 days.

There’s a transmitter part which plugs into the sensor and has a Bluetooth radio and a battery which is cheaper and lasts three months. You pop it off an old sensor and click it into a new one every 10 days until it expires.

IIRC the Dexcom G7 will have the transmitter built-in (and thus will also be disposable.) I'm happy about this b/c transmitter expiration anxiety is real with insurance companies being so stingy - you're lucky to get your new transmitter only a few days before the old one expires.