First word of advice: Apply as early as you can. It takes time for the application to be processed and you want it to start on the first day you are eligible. Don’t hesitate to follow up with Social Security if you are not seeing action or results, especially as offices are still closed to the public.
Tubed insulin pumps and insulin for tubed pumps are covered under Medicare Part B. Non-tubed pumps like Omnipod are not. Insulin for non-pump use is also not covered by Part B so you will need a supplemental plan to pick that up. CGM are covered, generally, and if you are already using one you shouldn’t really have a problem getting it transferred.
You will need new prescriptions once you start on Medicare for your equipment and supplies so try to make sure you have some extras in reserve before you start Medicare (if you can) so you can weather any delays.
You will need to prove you are type 1 by having a fasting C-Peptide test done AND a blood glucose test done at the same time. It is important that the test states it was done fasting even if the doctor has to write that information in him/herself.
Make sure you give all of your providers your new Medicare number when you get it. Medicare doesn’t notify anyone; you do.
It looks like everyone else has covered the other important stuff. Look closely at any supplemental/Advantage plan you choose to make sure it meets your actual needs rather than provides glitzy extras that may not be worth doing without what you really do need for provider coverage wise.
Again, the most important part - apply as soon as you can because it may take the whole 3 to 4 months to get it done. (I had to have a phone appointment - it was scheduled for 6 weeks later. I then had to do a follow up phone appointment after co-ordinating with my supplemental insurance - another 6 week wait, and it was literally approved the last day before I would have had no coverage.)