Here's a dismal retirement statistic that may come as little surprise: According to numbers crunched by the Employee Benefit Research Institute, three in 10 people are stuck working after age 65.

The ranks of workers toiling away past the traditional retirement age have swelled over the past 20 years. So that statistic probably has as good a chance of growing as do the gold coins accumulating in J.K. Rowling's vault at the Gringotts goblin-guarded bank.

You're probably already familiar with the trends keeping people chained to their cubicles. Fewer workers leave their jobs as freshly minted retirees with a fat pension and a health insurance policy in their pockets. Instead, they've probably been building a retirement cache mostly on their own. They may also have been told, with that final congratulatory clap on the back, that they'll have to seek out their own health coverage. The trend has spread to every sector, with companies such as Delta Airlines (NYSE:DAL), Sears Holdings (NASDAQ:SHLD), General Motors (NYSE:GM), and the Lucent division of Alcatel-Lucent (NYSE:ALU) among the many that have cut or considered cutting retiree health benefits.

Hear the warning bells
If none of this causes you alarm, and you relish the thought of remaining a productive member of the workforce for as long as you can, then quit reading and go back to work. But if you want the freedom to decide whether you stay on the job in your 60s, don't wait until your 64th birthday to get to work.

Being able to retire when you want means planning ahead. That means getting a start on your retirement savings now, whether you have 35 years or just five left years before the goal.

To say goodbye to performance reviews forever, you'll have to get a pretty good idea of what retirement will cost. If you're a long way from retirement, you might start with a few rules of thumb. You've probably heard the well-worn suggestion that you'll need to replace roughly 80% of your income to stay afloat in retirement.

That's a place to start, and it can get you on the road toward building your own vault full of gold coins. But if you want to get a little more serious about your retirement goals, you'll need to have a more specific plan of attack.

Make a plan
The Motley Fool's Rule Your Retirement newsletter service recommends you look at the retirement equation by asking yourself how much you want to spend when you're no longer working for a paycheck. Then, aim to build a pile big enough to enable you to withdraw about 4% of your money each year and live out all your retirement dreams with that sum.

You have most of the tools at your fingertips to explore this idea further. For the basics, get a good understanding of how and where to save for the future by visiting our Retirement Center. You'll learn the pros and cons of the different accounts available for retirement savers.

You'll also want to estimate how much life will cost in retirement. Take a look at the Fool's many retirement calculators to get an idea of how much money you'll save by getting rid of your job and its expenses. You can also look at the effects of inflation on your retirement savings and the benefits you can expect to get from Social Security.

Then, why not take Rule Your Retirement for a free 30-day spin? You can dig into its retirement strategies in depth, with access to the new research the service constantly generates to fine-tune its recommendations for building and preserving your retirement nest egg. With Rule Your Retirement's help, you can both reach your financial goals and keep your assets as safe as buried treasure.

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Fool contributor Mary Dalrymple apologizes to Harry Potter fans everywhere for her mystifying metaphors. She welcomes your feedback. The Motley Fool has a magical disclosure policy.