My husband and I made the financial decision that he could not retire until the year he was eligible for Medicare.
We had a small family biz so we paid both sides of FICA and our private insurance was over $1500 monthly for two people with a $10K deductible. (And the deductible HSA contribution of $7500).
He retired, Medicare kicked in, I'm on the ACA until I'm eligible for Medicare.
We are still very fortunate that we only go to the doc once a year.