Precisely Following This Savings Plan and You Can Retire in 15 Years Retirement is all about how much money you have and how much you need to live. Age is irrelevant.

When you think of retirement, you most likely believe that means working until you're in 60's, but here's the thing: retirement is a financial number, not a specific age. This means that if you follow the following savings plan, you'll be able to retire in fifteen years or less, regardless of your current age.

Set your post-retirement budget.

First things first, before you start stashing money away for your retirement, you need to know how much money you'll need to enjoy your retirement. This way you have a financial target to aim for.

If you've already established a budget for your life right now, then you're already ahead of the game. That's because you already have an idea on what your expenses are each month and how much you need to set aside.

Haven't created a budget yet? It's pretty easy to get started.

Eric Estevez states that you have two options. The first would be "to go through your bank accounts and credit cards to figure out where you spent every penny in the last month. Option 2 is to start a money diary. You'll log in every cent you spend over the next 30 days in order to grasp where everything is going."

"Lastly, you can back into what you should be spending on each of your expenses by separating your fixed expenses from your variable expenses. The goal is to understand where you money is being spent. It will be helpful in making realistic choices for a creating a successful budget."

After you've "broken down your numbers, you'll need to categorize them into buckets that make sense for you. Start with your income at the top of a spreadsheet and list out your expenses." Then you would deduct how much you spend each month on your mortgage, utilities, food, car, and so forth.

If you're spending more then you make each month, then you'll need to start making some changes. Save the extra cash that you have leftover.

If you work better with some hard numbers, then the Motley Fool states that you'll probably be spending about $3,700 per month - or about $44,600 per year. If you're using the 4 percent rule, then a nest egg of over $1 million will be needed to finance an "average" lifestyle.

Related: 3 Retirement Pitfalls and How to Address Them

Stop accumulating debt.

Remember, you're trying to save now so that you can retire sooner than later. This means that you should stop accumulating debt. This means living below your means and living a more frugal lifestyle.

Of course, that doesn't mean depriving yourself. It just means be smarter with your spending. For example, don't buy that new iPhone every year. Consider renting a smaller apartment or driving your used car a little longer.

But, most importantly, it means not spending what you don't have. Don't have the cash for a new wardrobe? Wait until you do instead of using your credit card.

Related: Retiring at 27: Ambitious, Lazy or Crazy?

Manage your career.

Since your career is your main source of income, it just makes sense to grow it as much as possible. ESI Money, which is a blog written by an early retiree, even claims that you can make your career worth millions if managed correctly.

This can be accomplished by doing the following seven steps.

Over-perform. Those who go above and beyond tend to get promotions and higher wages.

Be likeable. Some career experts rate likability above performance on the list of how to grow your career. Here's some skills you can start working on to become more likeable.

Network. Having a network of people can assist you becoming a better employee or even help you find a better job.

Be attractive. This is sad, but true. Studies have found that attractive people get "hired sooner, get promotions more quickly, and are paid more than their less-attractive coworkers."

Continue learning and developing skills. Pursue certifications, degrees , seminars, classes, training, and any other opportunities that make you an expert.

Know how to manage yourself. ESI states that in order "to be successful you will need a certain amount of skill at reading the winds of changes and ebbs and flows in your company and its employees."

Learn to market yourself. Make sure that you know how to sell yourself. This includes being an expert or knowing how to nail an interview or negotiate a raise.

Related: 5 Strategies for Women Entrepreneurs to Save for Retirement

Find multiple streams of income.

Even if you've been able to grow your career, having multiple sources of income ensures that you'll reach your financial goals. Since your goal is to retire in fifteen years or less, you'll need to make as much money as possible. And that involves having multiple sources of income.

In fact, Tom Corley, author of "Rich Habits," found that 65 percent of self-made millionaires had three streams of income. The first additional income stream you should focus on is through investments. The sooner that you do, the bigger your savings will grow.

Chris Hogan, author of the book, "Retire Inspired" suggests that you, "Spread your investments evenly across these four main types of mutual funds: growth and income; growth; aggressive growth; and international."

"By keeping your mix of funds equal, or close to it, you can take advantage of all types of market conditions and still protect your retirement from the ups and downs of stock market investing."

Since investing can be intimidating, or complex, I would suggest that you review this tutorial from Investopedia or speak with a financial advisor. However, there's also apps like Acorns, Robinhood and Tip Yourself that make investing and saving automatic without having to be an expert.

As for your other sources of income, consider side hustling. This could be a part-time gig like driving for Uber on the weekends, freelancing, or starting your own side business. The reason why this is so beneficial is because it helps you save more in less time. It also can speed up your retirement date since you're not solely relying on one source of income.

Related: This Doctor Who Lived to 105 Believed That for a Long Life, You Shouldn't Retire

Review and adjust your budget accordingly.

If you're earning more money, while decreasing your expenses, you should go back and revisit your budget. You may notice even more gaps where you can maximize your savings.

You should also run your numbers annually. This way your retirement income becomes more refined. Eventually, you'll notice that your retirement income is higher than your expenses. At this point, you've achieved your goal of retiring in fifteen years.

Related: Why Saving for Retirement Is a Waste of Time and Money

Putting it all together.

Let's say that you earn $50,000 at your job right now and will need $40,000 to cover your retirement expenses. The first step to take is to start saving $20,000 annually and investing. This should give you a 40% savings rate.

But, here's where things get good. If you've taken the advice listed above, you'll be able to land a raise. For argument's sake, let's say that earn 5% average raises. Save all those increases.

Now you're saving $20k every year on top of the amount of income that you receive over $50k. And, if your investments earn 8%, you're looking at $450k within a decade.

If you're eventually able to earn $18,000 a year from side hustling, you can add that to the $550k you have saved and invested.

Since you're currently allowed to withdraw 4% of your savings, you can withdraw $22,000 from the $550,000 you've saved. Add that $18k from your side business and you should be able to generate $40k annually.