Read your notice before the list
If you already have Medicare Advantage or Part D, the Annual Notice of Change says what changes on January 1. What to check before October 15 is the order of work. Write the doctor, the medical group, and the hospital with the My Medicare Checkup before you compare rows.
Three lists, three jobs
The Medicare Advantage list shows plans filed with CMS for a California ZIP, including premium, doctor visit, and the maximum you might pay in network. The Part D list shows the stand-alone California drug plans. It does not look up your prescriptions. The Medicare Supplement list compares standardized letters such as Plan G and Plan N. It does not show a premium. None of the three names a best plan.
What a row cannot tell you
A $0 premium does not mean your doctor is included. A star rating does not mean the plan covers your drug. Six Los Angeles County Advantage plans in the 2026 file do not include drug coverage, so a drug plan can be a separate choice. Check doctors and drugs on Medicare.gov. Medicare Advantage or a Supplement? is the question to answer before you treat the Advantage list as the only list.