When we moved across country my senior mom had to change from an HMO with drug coverage to traditional medicare with an supplement AND a drug coverage, just as that program was being implemented. We were advised that we needed to add some kind of drug coverage (any one would do), so that if she ever needed it, we would have it. They explained we could change to better coverage during open enrollment, if we ever needed it, but if we didn’t have anything, we couldn’t later add it.

Good advice, which we made sure we followed.