The most important thing you can do to keep healthcare costs from decimating your budget is to plan for them based on how much medical care you use now. Adjust your current costs for inflation (use 3 percent to 4 percent a year) to get a more accurate picture. Add in expected Medicare premiums, which run at least $1,600 per person per year. Also include extra for surprise costs, like needing a replacement crown. To help you estimate, AARP has an online retirement healthcare cost calculator (www.aarp.org).