I use the Dexcom CGM. The Dexcom company and manual will tell you you should change the sensor every 7 days. Many Dexcom users stop the sensor after 7 days, but do not remove it from their bodies. Then they tell the Dexcom to start the new sensor, which is actually the old one. The agreement with the fingersticks and meter is actually just as good, or better , during the second week. Some users have gone beyond the second week by renewing the same old sensor again. I begin having poor results after 14 or 15 days so I have been replacing the sensor after 14 days.
I don't think you can do this with the Medtronic Minimed CGM.