If you maintain health insurance from your union or former employer at the time for Medicare eligibility, you may apply for Medicare while keeping your current health coverage as long as your employer agrees to coordinate with Medicare.
Sometimes, individuals may opt to go with a Medicare Advantage Plan at the age of 65 even while being eligible for group coverage. Keep in mind - these health plans are private and are managed by unions or companies for you. They also receive funding from the government. Medicare Advantage Plans provide coverage for benefits that are typically covered in a regular Medicare plan. You will need to go network providers to receive coverage. You will also have restrictions not typically seen with Medicare Parts A and B.
For instance, there is a cap on Health Care Expenses ("Maximum Out-of-Pocket"). There is a way to limit out-of-pocket expenses with original Medicare as long as you purchase Medicare Supplement Insurance, otherwise known as Medigap. Either options provide you with many health benefits that are either inexpensive or without cost.
It is highly recommended that individuals still apply to Medicare, even if they do not automatically qualify and receive a Medicare card before turning 65. Head to Medicare.gov for more information on eligibility as well as access to a premium calculate. This will help you determine the expected costs.