Here's a look at six hidden or just underappreciated expenses you might face in retirement. Healthcare costsYou may be assuming that most of your healthcare expenses in retirement will be paid by Medicare, and that may be true. That doesn't even include long-term care, over-the-counter medications, or most dental services. It's costly because the cost of long-term care itself is costly -- and is often needed. Keep all these hidden retirement expenses in mind as you develop your retirement saving -- and spending -- plan.