In a month, personal income taxes are due. You still have time to fund a Regular IRA or a Roth IRA for calendar year 2015.

IRAs are a good way to save for retirement and everyone who can afford to fund an IRA, should consider doing it. There are different eligibility rules for each and which one you should use depends on many factors.

Among the key factors for picking between an IRA and a Roth are your current and future tax rates, when you’ll need the money and where it’s going.

If your tax rate is low now and may be higher in retirement, you might be more inclined to fund a Roth. If your tax rates are the reverse — high now, and low later — you’d be more likely to do an IRA.

Except for higher income people, contributions to an IRA are deductible but taxable on withdrawal. Roth contributions get no deduction but aren’t taxable if taken out after the account has been open for five years and the holder is over age 59 1/2.

If some of your money might go to a charity, a Regular IRA would be good since you won’t owe tax on the distribution (up to $100,000) if you are older than 70 1/2.

If you are younger than 50, you can contribute $5,500 to an IRA or Roth as can your spouse. Those older than 50 can contribute an extra $1,000 annually.

The younger you are, the more time your investments have to work for you. Regular contributions to IRAs or Roths can be a key part of your retirement savings.