Original Medicare (Parts A and B) does not cover 100% of any medical service or item; beneficiaries are consistently subject to out-of-pocket costs such as deductibles, coinsurance, and copayments. For instance, Part A requires meeting a deductible and paying daily coinsurance for extended hospital stays, while Part B typically covers 80% of approved medical expenses after the annual deductible, leaving the remaining 20% coinsurance to the patient unless supplemental insurance applies.