Just as we should all define "success" differently, how you define "retirement" is up to you.

Some people plan to retire and never work another day. Others plan to keep working, in some capacity, until they die.

However you define retirement, though, hopefully it includes the freedom to do more of what you want to do, and less of what you have to do -- which will require at least some amount of retirement savings.

If you're an employee whose company offers a 401(k) plan, the process is relatively simple: Sign up, maximize any match offered, and off you go.

If you own your own business or side hustle, you'll have to extend the entrepreneur's creed to planning for retirement: "If it is to be, it's up to me."

Here are five retirement account options, some designed specifically for small-business owners and solopreneurs, in order of simplicity to set up and ease of administration.

1. Traditional IRA

An individual retirement account (IRA) can be used by anyone (and a nonworking spouse) with earned income from a job or their own business.

Contributions are tax deductible, even if you don't itemize deductions. Say you earn $10,000 before taxes at your side hustle; if you contribute $6,000 to a traditional IRA, you will report -- and pay tax on -- income of $4,000. And you won't be taxed on any investment earnings until you start withdrawing money. (Keep in mind there can be penalties and taxes if you make early withdrawals.)

Opening a traditional IRA is easy; most banks and investment firms allow you to do everything online. At the end of the year you'll receive a statement to use when filing your taxes and boom: You're done.

2. Roth IRA

A Roth IRA is a variation of a traditional IRA. With a traditional IRA you contribute pretax dollars. With a Roth, you invest income that has already been taxed.

While that sounds like a disadvantage, there is one major benefit: Earnings in the account do not get taxed -- and when you start making withdrawals at retirement age, those withdrawals are not subject to income tax.

So you do get taxed on the money going in, but you don't get taxed on the money -- both what you contributed and any investment gains -- coming out.

The younger you are, the better that works out for you. If you're 30 and leave the money in your Roth IRA until you reach retirement age, even relatively modest annual returns could add up to a tidy sum -- a tidy sum you can withdraw tax-free.

Opening a Roth IRA is also simple.

Unless you make over a certain amount--then you'll have to add an extra step. And then you can still contribute to a Roth IRA. Even though you can't make contributions if your income level is above $139,000 if you file as single or $206,000 if you file married jointly, you can still do a Roth conversion. In simple terms, you contribute post-tax dollars to a traditional IRA, then immediately file a form to convert that IRA to a Roth IRA.

And boom: You've contributed to a Roth IRA. 


If you currently run your business by yourself but someday plan to have employees, a SEP-IRA (simplified employee pension) lets you -- as the employer -- contribute to a retirement plan on your behalf. (In other words, your company contributes, not you as an individual.)

On the plus side, you get to choose how much to contribute each year. But when you have employees, you must give them the same percentage contribution that you receive. (If the company contributes 10 percent of your pay to a SEP-IRA, it must contribute 10 percent of every employee's pay, too.)

Keep in mind you can contribute only up to 25 percent of your compensation, though. So you'll have to wait until you've calculated your profits and how much money is available to pay yourself as income before you determine how much you can contribute to a SEP-IRA. (Here's a calculator you can use to model different scenarios.)

SEP-IRAs are fairly flexible, though. If you have a great year, you can up the contribution amount. If results are poor, you can reduce or even eliminate the contribution amount.

Setting up a SEP-IRA is nearly as easy as setting up an IRA; most banks and financial institutions provide the option.

4. Solo 401(k)

First the basics. A 401(k) is an employer-sponsored plan (if you own a small business, obviously you are the employer) that allows you to invest pretax dollars in the plan. The employer may or may not match a portion of those contributions.

Like a traditional IRA, your savings grow tax-free. You don't get taxed on your contributions -- or any earnings -- until you start making withdrawals when you reach retirement age. 

With a solo 401(k), you can choose a traditional or Roth-style account, letting you choose to make pre- or post-tax contributions. 

One other difference: A solo 401(k) can be used only if you're self-employed and have no employees other than your spouse -- although if someday you do have employees, you can convert the plan to a normal 401(k).

If you make good money and don't have employees, a solo 401(k) is an easier -- and a little cheaper -- option than a "normal" 401(k). 

The biggest advantage to a solo 401(k) plan over the preceding plans is the significantly higher contribution limit. Unlike an IRA with an annual limit of $6,000 (or $7,000 if you're over 50), next year you can contribute up to $58,000 (or $64,500 if you're over 50) to a solo 401(k).

If you make good money and don't have employees, a solo 401(k) is easier to administer than a "normal" 401(k).

5. 401(k)

If you set up a normal 401(k) plan, roughly speaking you must offer the same plan benefits to your employees as you receive. So you may not want to establish a plan with a huge match.

But if you are your only employee, then you can feel free to match to your heart's -- and business's resources' -- content.

That's what I do. My plan is set up to match 100 percent of employee contributions, which means I match 100 percent of my contributions. Since I'm over 50 and can make "catch up" contributions, this year I can contribute up to $26,000 a year as an employee (if you're under 50, the annual limit is $19,500), and my employer (me) can match up to $26,000 a year.

That means I can potentially put $52,000 a year in retirement savings in a 401(k) alone. (Employee and employer contributions can't be greater than the individual's income, and can't be over $63,500 in total for us older folks.) Which means my company can kick in an extra $11,500 in profit sharing.)

And then I -- and you -- can still contribute to a Roth IRA.

Even though you can't make contributions if your income is above $139,000 if you file as single or $206,000 if you file married jointly, again, you can do a Roth conversion. 

Just keep in mind a normal 401(k) requires the greatest amount of paperwork -- both initially and at the end of every year -- and you will have to pay a provider a fee for administering the account. (Mine costs close to $1,000 per year.)

So make sure you balance what you can contribute with the costs associated; it probably doesn't make sense to set up a 401(k) if you plan to put, say, $2,000 into retirement savings. In that case, a traditional or Roth IRA is the smart way to go.

Later, when the amount you can contribute grows, then consider setting up a plan that allows higher contributions.

Then the additional effort and expense will be worth it.