I have had more costly issues with (lack of) coverage for the prescriptions, because most of them have limits on the number of pills that the
insurance will cover in a given period of time. For example,
azithromycin was covered for 6 pills every 28 days (and of course, "covered" means they will pay their part of it). I needed 24 pills every 28 days, so I had to pay the full cost of the 18 that were over what the insurance company determined was sufficient.