Americans approaching Medicare eligibility are often confused about when to stop contributing to a health savings account (HSA) when they are nearing age 65. These decisions are often overlooked due to conflicting timelines, including Medicare enrollment rules and HSA eligibility requirements. Jeffrey Levine, COO at Focus Partners Wealth, discussed these issues on a recent episode of "Focus on Finance Forum" and how to avoid excess contributions and tax headaches. Once enrolled in nonqualifying coverage, such as Medicare, you cannot contribute to an HSA once you are enrolled in Medicare. The effective date of HSA contributions can affect how much money is invested in HSA, and if you are only eligible for part of the year, your contribution limit may be prorated. The bigger issue is timing, as Medicare Part A is typically applied retroactively for up to six months if you enroll at age 70, so you should stop contributing at age 69½.