As of 2016, there were about 42.5 million U.S. households that owned at least one type of IRA, totaling about $7.5 trillion in assets. In other words, IRAs are a pretty popular investment tool. 

But they can also be confusing if you don't speak fluent financial jargon. If you're like most people, you probably wish you could simply throw your money into an IRA, forget about it for a few decades, and hope it all works out in your favor.

Unfortunately, it's not that simple, and it's important to regularly check on your investments to make sure you're on the right track to retirement. And if you're not taking advantage of all the different benefits of an IRA, you could be leaving money on the table.

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Traditional IRAs vs. Roth IRAs

First, it's important to understand the difference between a traditional IRA and a Roth IRA. They're similar in many ways, but they differ in regards to how they're taxed.

With a traditional IRA, the money you contribute can typically be deducted from your taxable income up front. The funds then grow tax-deferred until you withdraw them in retirement, at which point those withdrawals are taxed as ordinary income. Note that there are income-based limitations on who can deduct their traditional IRA contributions.

Roth IRA contributions, meanwhile, are nondeductible. However, your investments grow tax-free, and any qualified withdrawals you make will be tax-free as well. If your income is above a certain threshold, you won't be able to contribute directly to a Roth IRA -- but there's a backdoor method for high earners who want to take advantage of a Roth.

It's important to know the differences between these two IRA types. The last thing you want is to believe you have enough money to retire, only to realize too late that you'll lose a good chunk of your savings to taxes.

There are a few other things the average investor doesn't fully understand about the IRA, and these little-known perks could save you hundreds (if not thousands) of dollars.

1. You can contribute to both a 401(k) and an IRA

One of the most common retirement fund myths is that if you already have an employer-sponsored 401(k) plan, you can't contribute to an IRA.

There are a couple of reasons why you may want to contribute to both a 401(k) and an IRA. First, it allows you to contribute much more than the limits set on either type of fund. For 2017, the most the IRS will allow you to contribute to your 401(k) fund is $18,000 (or $24,000 if you're aged 50 or older), and the limit for IRA plans is $5,500 (or $6,500 for those who are 50 or older). If you're a power saver who wants to contribute more than the $18,000 that your employer plan will allow, opening an IRA may be beneficial.

Another reason to consider opening an IRA is if your employer plan has poor or limited investment choices. Because 401(k) plans don't typically offer many options in terms of where and how you want to invest your money, savvy investors may opt instead for an IRA for its wealth of choices. But if you don't want to lose your employer's matching contributions, you can invest as much as your company will match in your 401(k), then put the rest in an IRA where you can earn more for your money.

There's one caveat for savers who want to contribute to both a 401(k) and a traditional IRA: If you're covered by a workplace retirement plan, then you'll be subject to lower income limits on your IRA deductions. In other words, there's a greater chance you won't be able to deduct all, or any, of the money you contribute to your IRA. Read here for more details.

2. You can withdraw money without facing penalties

You've probably heard that you're not allowed to withdraw money from your IRA until age 59-1/2 because otherwise, you'll face a 10% early withdrawal fee and may have to pay taxes on that income.

While it's always a good idea to keep your money in your retirement fund until you actually retire (you don't want to get into a habit of withdrawing money on a regular basis, after all), it's not true that you can't withdraw your money for any reason without facing penalties.

For both Roth and traditional IRAs, the penalties are waived if you're withdrawing money for certain reasons, including covering a first-time home purchase, un-reimbursed medical expenses, certain expenses related to higher education, or health insurance if you lose your job.

Roth IRAs are a bit more flexible when it comes to withdrawals, because you've already paid taxes on that money. You're allowed to withdraw the amount you've contributed (but not your investment earnings) at any time, for any reason, without facing any penalties or tax payments.

3. You can benefit from an IRA if you're not employed

Another IRA rule you've probably heard thrown around is that you're not allowed to contribute to an IRA if you don't have a job. However, this is only half true.

It is true that you must be earning income in order to contribute to an IRA, but there's an exception for those who are unemployed but married to someone who is earning income.

Spousal IRAs are designed for stay-at-home parents and spouses who are unemployed but want to continue investing. To qualify for a spousal IRA, you'll need to be married and filing a joint tax return. The IRA will then be opened in the nonworking spouse's name, and the amount you're eligible to contribute will be dependent on how much the working spouse earns.

The working spouse will have to earn enough to cover their contributions to both their own IRA and the nonworking spouse's IRA. For example, if a 35-year-old wants to contribute the maximum amount for themselves and their nonworking spouse, they'll need to be earning at least $11,000 (that's two times $5,500, the individual contribution limit for a 35-year-old).

There's no doubt that IRAs are complicated and confusing sometimes, but taking a few extra minutes to learn how they work, and the incredible perks they come with, could save you loads of cash.

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