I turn 65 in November 2024. I already have been notified by Social Security that my Medicare parts A and B will start the same month (I have decided to start Social Security in 11.2024 as well). I know that I will be going with a medigap plan G and part D for prescription drugs. (I will more than likely be going with AARP/UHC since I know that the providers I am currently using are using them as well.) Obviously, I want both of these to start in November as well. I understand that any changes for Medicare supplements for 2025 will be known by open enrollment (I think it starts around the middle of October and goes until December). My concern is mostly with part D for prescription drugs. I am on several prescriptions, some of which are expensive. Since I am starting Medicare so late in the year, my 2024 part D premiums as well as the formulary may change two months later. In order for my coverage to start 11.1.2024, what is the latest day in October for me to signup without delaying coverage for another month? The reason I ask is because of the 2025 changes being released to the general public starting in mid-October. This will allow me to have a little time to compare 2024 and 2025 changes. I hope that all of this makes sense. I live in Orange County, California if that makes a difference.