I order transmitters when the warranty expires; in other words every six months. My last transmitter lasted 7.5 months. My longest lasting transmitter was 9 months. Even though my warranty expires doing this, I always have a transmitter on hand to immediately replace a failed one. Insurance pays for 80% of my transmitter cost.
If I were self-funding, I would seriously consider waiting until the receiver warning happens. If you pay attention to that and make an immediate order, you should be OK. I’m in California, about 500 hundred miles away from Dexcom headquarters. I usually receive shipments 2-3 days after my phone order. If your Dex source is equally responsive then this plan could work.
Since you place importance on your Dex working during holiday, perhaps you could order a replacement, bring it along with during the holiday as a backup. I did that on my last holiday. The new transmitter, in its original box, is small and light. The only real danger I see in this plan is losing the transmitter during your travel.
Next time you change your sensor site, I would take extra time to clean the two contacts on the bottom of the transmitter. Dexcom recommends isopropyl alcohol. I’ve also used a clean pencil eraser followed by the alcohol or even just soap and warm water.
Perhaps I should have mentioned this first. Are you sure your transmitter is fully seated into the sensor pod with both wings holding down the transmitter tabs? Sometimes the location of the sensor does not give a clear line of sight to see that the transmitter is fully seated. I use a mirror if I’m not sure this is true. Listening for both clicks is key when seating the transmitter.
Now I know that the user manual warns against doing this, but when I see data dropouts and loss of signal, especially when it occurs after a shower or bath and I’ve visually confirmed that both sensor pod wings secure the transmitter, I will actually remove the transmitter from the sensor pod, thoroughly dry, with a hair dryer, all the surfaces and then reseat the transmitter. This can be awkward to do, especially without the lever that’s present at initial installation, but I’ve done it several times. It involves pressing firmly against the sensor site while listening for the " click-click." Getting help from someone else would be easier. There is a danger of moving the sensor wire under the skin and ruining the site but I have not experienced that yet.
Good luck! Please post whatever you decide to do or discover.