If you've held a job or paid your taxes, you likely know what an individual retirement account (IRA) is. But there are a number of offshoots and IRA-adjacent accounts that anyone looking to retire someday should know about.

Here are five types of IRAs and why they matter.

Individual Retirement Account (IRA)

This is a traditional retirement savings account that offers a tax deduction for the tax year in which the contribution was made. It's become an important part of the retirement lexicon in the U.S. lately, as a recent study from Pew Charitable Trusts found that 35% of private sector workers don't have access to an employer-based retirement savings plan. In that case, IRAs are a useful tool for saving when your job doesn't offer something like a 401(k)-matching plan.

You can contribute to an IRA as much as you want up to a predetermined amount every taxable year, and that sum grows once you turn 50. In 2017, the contribution limit for an IRA was $5,500 for anyone under 50 and $6,500 for anyone over 50. Your contribution can't exceed your earned income.

The investment can sit and grow tax-free until you choose to begin making withdrawals, which typically isn't allowed until you reach 59 ½ years old. If you withdraw money from a traditional IRA before you hit 59 ½, you could be slapped with a 10% penalty on the amount you withdraw. That's in addition to regular income tax you'll owe on the earnings.

Roth IRA

Roth IRAs offer investors the opportunity to contribute money after taxes, then take out their contributions and earnings in retirement tax-free. Withdrawals are usually tax-free as long as the account has been opened for more than five years and the investor is more than 59 ½ years old. Contributions to a Roth IRA, though, aren't tax deductible like traditional IRAs.

A Roth IRA, like a traditional IRA, usually has an income threshold that keeps very high earners from qualifying to make contributions. Those high earners might qualify instead for a nondeductible IRA.

Rollover IRA

This becomes important when changing jobs. If you're looking to transfer assets from one tax-deferred savings vehicle into another plan, consider a direct transfer into an IRA rollover account. If you do that, you can keep the money separate from your traditional IRA and later move it into a new employers' 401(k) plan after meeting the predetermined length of employment requirement.

Self-directed IRA

A self-directed IRA is set up with a brokerage, but the investor has the responsibility of determining how the money will be invested. It could go toward stocks, bonds, real estate, nontraditional investments and more.

You'll need a trustee or custodian who has expertise in nontraditional savings accounts, and that could sometimes run a hefty fee. These IRAs are typically considered higher risk, higher return given their broader portfolio diversification.

SIMPLE IRA

A savings incentive match plan for employees (SIMPLE) IRA allows people who work for companies with 100 people or fewer or people who are self-employed to contribute to an IRA like they might a 401(k).

This money is taken from income before the worker receives a paycheck, but it is taxed as income when taken out at retirement. There are beneficial tax deductions associated with contributing to a SIMPLE IRA, though.

Retirement Is Complicated. It's never too early -- or too late -- late to plan for and achieve your retirement goals . TheStreet's new premium subscription, Retirement Daily, will help you uncomplicate the world of retirement with the latest, news, research and analysis from TheStreet's "Mr. Retirement" Robert Powell and his team of experts. Learn more about Retirement Daily and get a free trial subscription.

More from IRAs

Best Funds to Boost Your Retirement Portfolio -- Especially for Younger Workers

Best Funds to Boost Your Retirement Portfolio -- Especially for Younger Workers

New Ways to Save for Retirement: Try BFFS and SeLFIES

New Ways to Save for Retirement: Try BFFS and SeLFIES

How Technology Is Disrupting Retirement Planning

How Technology Is Disrupting Retirement Planning

4 Critical Questions to Ask Your Financial Advisor

4 Critical Questions to Ask Your Financial Advisor

Best Ways to Save for Retirement - Even When You're Living Paycheck to Paycheck

Best Ways to Save for Retirement - Even When You're Living Paycheck to Paycheck