At this point she has no supplement or drug plan. My understanding is there are substantial penalties required to get back on these plans or onto an Advantage plan. She would not qualify for Medi-Cal because of Social Security and the part time job.
I don't think there is a penalty to get back on a Medigap plan, but she might have to undergo approval at that age. However, California has some special rules for Medigap plans so I think it is worth doublechecking.
Also, I have never heard of any late penalty for getting on a Medicare Advantage Plan, and again, many have zero premiums. I personally would never go with just Parts A and B, especially when there are so many helpful plans available. One important thing is to choose one which includes the location and providers of her preference.
As far as the Part D for Rx, I personally think the late enrollment penalty would be worth it for someone in their mid-70s and there is an explanation at Medicare.gov, and I personally think well worth it to pay some extra dollars to have it rather than need even one med which could be very costly out of pocket. Also, recent law changes have made Part D even better now and in the coming years. In 2025 the max out of pocket copays will be limited to $2000 per year with the option to break it up into monthly payments, from what I read.
Don't forget, one can also get many meds very cheaply through various discount programs like GoodRx, etc., but again, I think Part D is important, well worth it, and many people at least sign up for a cheap plan to at least have something to fall back on, and even with the penalty added on, could very well be worth it.
One can go to Medicare.gov and it has drop downs to look at various Part D and Medicare Advantage plans in her area. Very helpful.
Again, I would look into the "Extra Help" subsidy for Part D--if approved, copays can be lower and there is no late enrollment penalty.
