This article is part of a series about the FIRE Movement and how investors can apply these principles to their lives, compiled by InvestorPlace.com.

The average American retires at the age of sixty-five. And there’s nothing wrong with retiring in your sixties, but what if you didn’t have to wait so long? What if you could save up enough money to retire in your fifties, forties or even earlier?

FIRE seekers around the globe are bucking the trend of traditional retirement and leaving the workforce decades before their coworkers and peers.

The Definition of FIRE

What is FIRE? FIRE stands for Financial Independence Retire Early. It’s a set of rules created to redefine your relationship with money. FIRE allows you to think about possibilities (like early retirement) that you’ve never considered before.

The first half of the acronym FIRE stands for “financial independence”. To become financially independent your passive income streams should cover your annual expenses.

Most early FIRE seekers relied on passive income from investments. These days the definition has broadened to include rental properties, royalties and online income.

Once you reach financial independence you no longer need a traditional 9-to-5 job to pay your bills. FIRE seekers aim for a net worth of at least twenty-five times their annual expenses. The amount you need to save depends on how much you spend each year.

These figures vary based on your lifestyle. For example, if you spend $100,000 annually, you’ll need $2.5 million worth of investments. If you spend $40,000 per year, you’ll need $1 million.

Minimizing your lifestyle helps decrease the amount of money you need to save. The less money you need to pay for your basic expenses, the less you’ll need to accumulate before you retire.

Which brings us to the “RE” part of FIRE. RE stands for “retire early.” The truth is you don’t have to retire early just because you reach financial independence. The goal here isn’t necessarily to quit working, but to no longer rely on full-time employment to pay your bills. If you love your job, you can continue to work, but if you don’t you can choose to retire early.

Cut Unnecessary Expenses

Now that you know what FIRE is, you might be wondering how you can get in on the movement. To begin, you must carefully track your expenses: you’ll need to figure out where your money goes. Pull out your credit card statements and audit your purchases line-by-line.

Are you using the services you pay for? If not, start cutting them. If a purchase isn’t necessary, important or bringing you joy consider cutting it out of your budget.

Start with small expenses, then figure out ways to decrease your three biggest expenses: housing, transportation, and food. These will have the largest impact on your bottom line.

Keep in mind that FIRE is about frugality, not austerity. Despite what people may say, it’s about making wise decisions with the money you earn. The plan is to reduce your expenses while redirecting your money to activities you enjoy.

If you are struggling with this step, think hard about your future plans. You cannot achieve FIRE by spending all of the money you earn. Trimming unnecessary expenses today ensures a future full of flexibility.

Save More and Save Often

When you limit your spending, you create more space for saving. Many FIRE proponents suggest saving 50% to 60% of your annual wages.

If that seems impossible, start with a smaller number and work your way up. Typical retirement advice suggests saving 6% to 10% of your salary, but those numbers won’t work here. You need to save a whole lot of money to knock decades off your career.

Look for ways to increase your salary by putting in extra hours at work or going above and beyond the call of duty. Avoid lifestyle inflation by putting bonuses and stock awards directly into your savings.

The easiest way to achieve FIRE is to earn a six-figure salary, but that doesn’t mean those with lower incomes can’t do the same. It just might take a little longer. Creative money-making solutions can also help; a lot of FIRE seekers look for extra work through the gig economy. You can start a side business, drive Uber, deliver groceries or sell products on eBay or Etsy.

Invest

After you earn that extra money, you won’t want to stash it under your mattress. To achieve FIRE, you can’t just save; you have to invest your cash. Investing accelerates your timeline to FIRE significantly.

Some FIRE seekers are great at decreasing expenses. Others have no problem increasing their salaries or saving exorbitant amounts of money. Unfortunately, many in both categories are hesitant to invest.

If you want to retire early you must allow your money to start earning money for you. Think of your investments as an extra helping hand. The faster you can build this passive income stream the faster you can reach financial independence.

Remember to balance your investments in retirement and non-retirement accounts. Retirement accounts will provide extra savings after the age of 59 ½, but that won’t help if you plan to retire at age 40.

Brokerage accounts and Roth IRAs are the go-to accounts for young FIRE seekers. Load these accounts with dividend-producing stocks. Those dividends will help replace your income after you retire.

Dream Big

Before you race off to save as much money as possible, keep in mind that FIRE is not all about money. In fact, the biggest question you ask shouldn’t be, “How much money do I need?” It should be, “What will I do after I become financially free?”

Spend some time dreaming about your future. What do you want to do one, two or three decades from now? Even if you love your job you may not want to continue working for the next thirty to forty years.

Think about your future and it will be easier to strive for FIRE. Creating and executing a solid financial plan won’t be easy, but it will be incredibly worthwhile.

One Frugal Girl is an ex-software developer turned FIRE adherent who runs a finance blog. You can find more of her writing about managing your personal finances here.