Roth vs. traditional IRA differs on the tax implications and whether you’re earning above a specific ceiling, and whether you have another retirement funding option.
(caveat: I know I’ve forgotten some of the details re traditional IRA; we do most of our retirement savings through our 401(k) as we need to reduce the tax hit right now and we don’t qualify for a deductible IRA. Any extra goes into the Roth IRA).
Traditional IRA can be deducted from your income tax, if your income is below some specific levels, and you don’t have a 401(k) or other retirement plan through your work. So if you’re earning 50,000 a year, and you deposit 5,000 in an IRA, your taxable income is only 45,000 a year. If you’re at a 20% tax bracket, you’ve just saved 1,000 dollars on your taxes. Then that 5,000 grows (hopefully!!!) for the next 40 years. Then when you retire, let’s say that 5K is now worth 40,000. You pay taxes on that 40,000 as you withdraw it. Hopefully your tax bracket is lower at that point (let’s say 15%).
The traditional IRA becomes non-deductible if you have a retirement plan through work and your income is above a certain level. Same scenario as above, only you don’t have the instant 1,000 savings. And when you retire, you don’t have to pay income taxes on the original 5,000, just on the 35,000.
A Roth IRA is not deductible. Same scenarios as above, but you don’t save the grand on taxes this year. HOWEVER - when you retire, you’ve got that 40,000 FREE AND CLEAR. No taxes.
In general, a traditional IRA is preferable (IMO) if you need the income reduction now, and think you’ll have lower income in retirement. A Roth is preferable if you don’t need (income too low) or can’t take (income too high( a deductible IRA, and/or you think your income in retirement would be higher than it is now.