Type 1 Dexcom G6

I'd do it at a time convenient for you

You could either put the new one at some useful time the previous day and end the old one and start the new one or yes wait til the next day, obviously if you wait til the next day you will have a period with no monitoring (ie from when the old one runs out til the new one starts) but until CGM's appeared recently-ish we never had that data anyway

Note: I don't use a Dexcom (I use a different one that works with my pump), but all the CGM's work in essence in the same way, ie. it doesn't matter if you have a break (long or short) just means you wont have the data for that missing time period (edit:typo)

As a Dexcom user I had a similar issue. Old sensor died at about 10.30pm. Change over, 2 hr warm up and an annoying alarm about 12.30 telling me I was back online.
To get back to a more reasonable time I just ended the sensor session at 7.30 pm ( lost 3 hrs of usage ) removed old sensor and started a new sensor. Along with 2 hr warm up I was back online by 9.30 pm.
Also remember you can stick the new sensor on in advance of taking old sensor off. This cuts down on the changeover time.

EllieM said:

I personally find my dexcom can read a bit low for the first 12 hours, so was getting fake night time hypo alerts when I put one on in the evening....

I just went without overnight to get back to a morning start up, but of you don't want to do that you can, as @therower said, you can end the old sensor early (stop sensor is at the very bottom of the settings menu). Not sure how much help putting the new sensor on early is though, as you still have to wait two hours after activation for warm up, though I guess it might reduce new sensor inaccuracies?

Click to expand...

I found putting the new sensor on prior to the old one expiring saved me about 10 mins ( every little helps )
By the time I’d shaved , wiped, skin tacked, unwrapped and stuck the new sensor on I’d wasted precious my time.
There is also an argument for letting new sensors bed in as it were, giving better accuracy earlier after activation as you alluded too. Personally I find Dexcom to be quite accurate from the outset.