Your HSA is an awesome place to save money. You can contribute pre-tax money to it, or post-tax money with a tax deduction. You can invest in stocks and grow your money tax-free. Like a 401(k)/IRA, you can withdraw money for retirement. Or you can withdraw money anytime for medical expenses. That's triple tax savings, which is better than any other type of savings account.

You can contribute to an HSA if you have medical coverage under a high-deductible plan. And you can't be someone's dependent, be on Medicare, or have medical coverage in your or your wife's FSA.

The contribution limit for an individual is $3350 (2016) or $3400 (2017). For a family, it is $6750 (total).

You can still contribute after-tax money to an HSA until 4/15 (tax extensions do not extend this deadline). You'll get a tax deduction on your income taxes for the after-tax contribution, but you'll still be paying about 7% more in taxes compared to a pre-tax contribution because of payroll taxes (social security, Medicare).