Source: Ian MacKenzie via Flickr.

For many investors, the "finish line" is often viewed as reaching their goal of retirement. But there is no set path for people to follow in order to achieve their "goal," as everyone's social and financial situation is unique. And life doesn't simply come to a halt once you retire, therefore neither can your investing.

To illustrate this point, I want to share with you five of my favorite quotes about retirement. If you can look beyond the simplicity of these quotes and see the broader meanings they imply, you can apply what you learn to become a better investor now and after you retire.

"Don't simply retire from something; have something to retire to."
--Harry Emerson Fosdick 

This retirement quote always strikes me as relevant because I've seen far too many people retire at a specific target age and then, following a few months or years of retirement, wonder why they're so bored. The reason is that their planning for retirement ended with reaching retirement, with no consideration of how they wanted to spend retirement.

When you're planning for retirement, your goals should remain fluid so you constantly have something to strive for. Further, planning how you'll spend your golden years doesn't begin the day you retire. As with investing, it should start as early as possible and continue throughout your working and retired life.

"The question isn't at what age I want to retire, it's at what income."
--George Foreman 

Source: Tax Credits via Flickr.

After thrilling the nation in the boxing ring and bringing indoor grilling to the masses, George Foreman is now dishing retirement quotes you can take to heart.

The quote above is a great reminder that retirement ages aren't fixed; they're unique to everyone. Some people will be able to retire earlier than others.

People should retire when they feel they have the means to live comfortably given the type of retirement they want for themselves. For some, this means collecting Social Security at the "early-retirement" age of 62 -- the first point at which they're eligible to do so. Others, however, might choose to wait until age 70 to allow their Social Security disbursement to grow over time while living off their other retirement savings.

In other words, retirement is ultimately what you make of it, and you remain in the driver's seat at all times.

"As far as your personal goals are and what you actually want to do with your life, it should never have to do with the government. You should never depend on the government for your retirement, your financial security, for anything. If you do, you're screwed."
--Drew Carey 

This is a great reminder for both young adults and those nearing retirement that the landscape of government benefits, especially Social Security, could look drastically different in 20 years. Translation: You and only you are in control of your financial destiny.

Unless Congress acts soon, the Social Security Trust Fund will exhaust its reserves somewhere between 2033 and 2037, depending on which source you choose to believe, and benefits for new qualified retirees could drop to just 75% of their current "full" benefits. This is why it's so important to maximize contributions to your retirement accounts now so that compounding gains can work in your favor.

A Roth IRA, for instance, is a retirement account that allows annual contributions of up to $5,500 as of 2014 ($6,500 for those aged 50 and older) and can grow completely tax-free over time. Just imagine what decades of dividends and compounding gains could do if you started contributing 30 to 40 years before you needed to start taking distributions!

"I feel that one of the most important lessons that can be learned is that what we 'see' may be different than what is actually in front of us."
--Mark Singer, author of The Changing Landscape of Retirement -- What You Don't Know Could Hurt You 

The implication here is that when we assess our readiness for retirement we have the potential to be blinded by a false sense of safety. Some people incorrectly believe that just because they're going through the retirement-planning motions, they'll have the funds to cover their expenses in their golden years.

But the world is a dynamic place, and nothing is constant. We are living longer than ever, inflation is pushing the cost of goods and services higher, and Social Security is on the precipice of a major change. Long story short, though you might think you have enough cash to last until the end of your days, you may be unpleasantly surprised when the world throws you a financial curveball.

There's no way to know exactly how much is enough when it comes to your retirement, but the point here is that investors and retirees need to be able to adjust their objectives as their economic surroundings change. Don't be afraid to reassess your financial situation often, and remember that investing for your future shouldn't stop just because you've retired.

"Age is only a number, a cipher for the records. A man can't retire his experience. He must use it."
--Bernard Baruch 

Source: U.S. Army via Flickr.

Lastly, this retirement quote from Bernard Baruch, I believe, sums up one of the most understated "missions" of retirees: to pass their knowledge on to their peers and to younger generations.

One of the great aspects of The Motley Fool is that it's a collective stomping ground of opinions, ideas, facts, and prognostications from all walks of life and all age groups. Sure, we could all go at investing alone and believe we've learned everything we need to know from reading a few dozen investing books, but you'll find much more value in both your life and investing world by sharing your experiences in an effort to grow collectively.

In sum, don't forget that we're all heading toward the same general goal on our own unique paths, so be sure to help others out along the way.