You can spend a lifetime and still not know everything there is to know about investing -- not even close. Just look at Warren Buffett, chairman and CEO of Berkshire Hathaway. He's 92 and has been investing his entire adult life, and while he is considered one of the greatest investors ever, he still makes mistakes.

On the other hand, you do not need to be Warren Buffett to be a successful investor. You can grow your retirement portfolio by a factor of 10 or more by just doing a few very simple things.

Invest in your employer-sponsored plan and get the full match

If you are not investing in your company's 401(k) or employer-sponsored plan, this is the first step. Most workers with access to these types of plans take advantage of them, according to data from the U.S. Census Bureau, but participation does trend lower for younger workers. That's unfortunate because millennial and Gen Z workers are the ones that will get the most out of their plans because they have longer time horizons to save, invest, and compound their savings -- as I will show later on. So, it is imperative that they start contributing as soon and as early as possible.

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But setting aside a portion of your salary for your 401(k) is only part of it. The other imperative is to get the full company match. The best feature of a 401(k) plan is the company match, which means the company gives you free money up to a certain percentage that you contribute. The match varies -- for some, it's 4%. For others, it is 2%, and some might give you a 50% match on the first 6%. There are also tiered matches, where an employer might match 100% on the first 2% and 50% on the other 2% up until the limit. Not all companies offer a match, but most do in some form or another.

The most common match is 100% up to the 4% that you contribute every paycheck, so let's do the math and see how fast that can grow.

A millionaire by retirement?

If you are, say, a millennial, 30 years old, earning $40,000 per year, here's how you could turn that into over $1 million by retirement. Based on a $40,000 salary at age 30, with a 4% annual contribution to your plan, and a 4% employer match, factoring in a 3% raise every year until you retire at age 65, you would have about $1.2 million in your retirement savings by age 65. That assumes a 10% annual investment return, which is the long-term average of the S&P 500.

If you want to be more conservative and assume a 2% raise each year and an 8% annual investment return, you would have about $711,000 at age 65.

Now, let's say you didn't start saving in the plan until age 40 -- as you worked somewhere without a 401(k) or just didn't start saving for whatever reason. Based on a salary of $50,000 at age 40 -- and plugging in all of the numbers from the first scenario -- you'd have about $526,000 after 25 years at age 65. So just by starting 10 years earlier, you would double your money at retirement.

If you want to play with these numbers, contribute more or less, or assume a different salary, annual raise, or investment return, you can find a 401(k) calculator online and do the math yourself.

But this just shows how you can grow your retirement savings by leaps and bounds by simply starting to invest as early as possible and taking full advantage of your company match.