Hearing aids are among the more expensive medical devices people buy out of pocket, and they are fully deductible as a medical expense. The IRS includes hearing aids, batteries, and related maintenance costs as qualified medical expenses. If you itemize your deductions and your total medical expenses exceed 7.5 percent of your adjusted gross income, you can deduct the out-of-pocket cost of your hearing aids. You can also pay for hearing aids using an HSA or FSA with pretax dollars, which avoids the need to hit the deduction threshold at all. Given that hearing aids can cost several thousand dollars per pair, these accounts are worth considering.