If you return to work and can obtain adequate workplace health coverage as primary coverage, you may discontinue Medicare and re-enroll without penalty. If you drop Medicare and do not have creditable employer coverage, you will be penalized when you reapply for Medicare. The penalty is $0.5 million for each year after 1978 that you fail to apply. As long as you remain below the age of 65, any job with employment insurance (such as a union job) will provide sufficient coverage. If you stop working before you reach retirement age, then you must continue paying into Social Security until you earn over four times your annual salary in wages from work done during career years (35 to 40). At that point, your payroll taxes will be deducted from your paycheck by your employer. This arrangement is called "payroll deduction" because your employer sends your tax payments to the Social Security Administration (SSA). If you start work before reaching age 25, you can add certain hours of employment to your credits up to a maximum of 10 years of credits. For example, if you begin work at 24 years old, then you could earn up to 104 credits over 10 years by working only 50 hours per week for 50 weeks per year. In this case, you would need to pay a 6% penalty on any earnings in excess of $120,000 ($150,000 if you are over age 35).