The Freestyle Libre requires a prescription (why?) — is there another similar system that does not?
I believe the thinking is that people need a professional to discuss results with. I understand that perspective, but I don’t agree with it, and I definitely don’t agree that having someone to discuss results with should outweigh the increased access/adoption of over-the-counter sales. This is the first product that makes it practical - even easy - and completely painless for non-diabetics like me to track blood glucose informationally, so perhaps this will change. That said, the FDA has made other overly-conservative decisions, like disallowing fingerstick A1c tests (which don’t require fasting or a full venous blood draw) for first-pass screening of diabetes: http://www.onsitehealthdiagnostics.com/blog/a1c/, https://twitter.com/troyd/status/1018150306125758465.
The problem with Dexcom is the price. A sensor should be replaced every week and costs 80€, the transmitter turns off after three months and costs between 300-400€. If you understand what you're doing, you can easily extend the sensor lifetime to 3-5 weeks and transmitter to 6-8 months.
My take to this is, every T1 deserves a Dexcom system from the insurance. It easily saves your life and makes the control much easier.
Some sensors get noisy sooner than the others. I noticed they work longer during the winter when its cooler. Last one worked for 4 weeks quite good, but in the summer they stopped working in less than two weeks.
I found some pictures of someone replacing the battery on the transmitter of a G6. This is.... not really practical. [1]
What would be interesting is if you could pull out the internals and 3D print a new enclosure that had an actual user serviceable battery.
[1] - https://seemycgm.com/2018/07/12/g6-transmitter-battery-repla...
As a side note, I think this requirement is completely bogus. You should be able to get any "read-only" medical device you want, anytime you want, especially in a country where there is no universal healthcare. I see a contradiction where on one hand the authorities say: we have to protect you so that you don't harm yourself and on the other the same authorities say: your health is your responsibility and we want nothing to do with it.
It does seem like a helpful tool to screen.
Here in the UK, I don't have a prescription (despite being type 1 diabetic) but occasionally self-fund the devices directly from Abbott. I get a VAT excemption so it costs ~£45 per unit, which lasts 2 weeks.