Part C plans must provide the required Medicare benefit coverage, but networks, referrals, prior authorization, cost sharing, and additional benefits depend on plan type and terms. Compare the person's providers, prescriptions, likely care, and total cost—not just the premium.
A $0 additional plan premium does not ordinarily remove the Part B premium obligation or all service costs. Some plans offer a Part B premium reduction; that is a specific benefit to check, not a universal feature.
Medicare Advantage has an annual limit on the member's out-of-pocket spending for covered Part A and Part B services under the applicable plan rules. That medical limit is separate from Part D drug spending. Premiums and noncovered services are not automatically included.