If you’re over 60 years old and reading this post, it’s probably too late. Good for you if you’re under 30. You’ve got a better chance if you’re younger.

Age discrimination? No. The end of retirement as we know it — an emerging unpleasant reality that will (re)shape the quality of life and standard of living for billions. Start dealing with it. Now.

If you are a knowledge worker, cognitive capitalist, or a Reichian symbolic analyst, you will not be retiring at 65. Period. Even if you are in a protected public union with cosseted pension funds, you are at extraordinary risk. Just ask the Greeks, the Californians, or the Japanese. This is a global phenomenon. Demographics and structural deficits don’t lie. Unless the global economy comes roaring back in ways that stimulate sustainable growth in OECD countries, even the most talented professionals had better expect to work for at least another five years.

Of course, with stimulating careers, good health, and longer life spans, this isn’t necessarily a bad thing. But it is surely not what most mid-career executives and professionals have planned. (Indeed, there’s no shortage of optimists who still expect to enjoy the fruits of early retirement.) Forget the “saving for retirement” shibboleths. Strategically addressing those 60+ months after age 65 may be the most significant long-range planning investment in your human capital portfolio. Charles Handy’s “portfolio careers” and “How Starbucks Saved My Life” scenarios notwithstanding, the simple reality is that retirement planning as we know it is obsolete.

Everyone reading this should take 15 hard minutes to ruthlessly reassess the reality of the “new” final years of their future career. The finish line has become elusive; the goal posts have been pushed back. Based on your current skill set and competences, what do you think your workday will look like when you’re 70? Are you comfortable with the probability that you will be managing employees younger than your grandchildren? Temperamentally, do you think you’ll add more value as a mentor, a partner, or part-timer? More important, what will your (much) younger boss think?

Do you honestly believe that, when you have to work five more years than anticipated, you can get away with not being more facile, adept, and productive with emerging technologies? The inevitable aging of the (for now) wealthier Western economies guarantees a surge of innovative device interfaces more compatible with slower fingers and tired eyes. You will, of course, be taking web-enabled professional/technical development courses at 58 or 62 or you will be fired for cause.

Whatever your 70-year-old workday scenarios may be, what new or novel skills or experiences do they demand? Do they demand more travel or less? More time immersed in digital environments or less? More interactions with people within a decade of your age or fewer? Are there personal or professional development initiatives you should be undertaking now precisely because those five years present opportunities that the earlier deadlines don’t?

The most important slice of those 15-minutes-for-five-more-years should focus on role models. Who are the 70+ year olds whose presence, energy, and effectiveness might profitably serve as the benchmarks for your own? Who are the two 75-year-olds who you would professionally emulate? Write them down. I know my two and why I picked them. But why have you chosen yours? What do your choices say about the kind of person you want to be at the end of your professional life?

To be sure, there’s no shortage of 70+ and even 80+ seniors — Warren Buffett, Sumner Redstone, Pablo Casals, Louise Nevelson, Agnes de Mille, Lee Kuan Yew — for whom advancing age has not been an obstacle to productivity and professionalism. But the braver and bolder way to interpret this challenge is the recognition that, just as you can’t run or swim as fast as your 25-year-old self, your 70-year-old self will have to manage and add professional value differently than you did at 40 or 50.

You don’t have to know — you can’t possibly know — the answer to that right now. But it’s not too early to ask those questions and select those role models. (You’ll be fascinated to see how those selections evolve as you age). The future of “five more” doesn’t quite make a mockery of the clichéd “Have you saved enough for retirement?” and “What will you do in retirement?” questions dominating most end-of-career discussions. Make no mistake: Calculating the value of career-enhancing investments at 53 when expecting to retire at 65 requires different NPV or DCF computations and professional assessment than when making such a bet knowing you will not be retiring before 70. That’s a greater than 40% gap; it can’t be ignored or finessed. The changing structural economics of retirement almost completely overturn conventional cost/benefit calibrations for human capital investment.

Are those extra five years being tacked onto an appreciating or depreciating asset? Even adjusting for age discrimination lawsuits and legislation, how will organizations accommodate a psychographic, demographic, and economic shift every bit as profound as the rise of women in the workplace?

The fact remains that older professionals and managers tend to be the most expensive items on the payroll. You know this. What on earth justifies the value of keeping them — or you — for five more years? Or, alternately, are those additional years spent in the murky realms of partial, part-time, or contingent employ with nervous 60-year-olds working almost as hard and creatively for two-thirds or three-quarters of their previous compensation? How about half?

The pace of change in the most vibrant post-industrial sectors is such that the technical expertise of one’s 40s has decayed into anachronistic obsolescence by one’s 50s. Knowledge may be power but it is also perishable. Yesterday’s hot mark-up language is tomorrow’s Sanskrit; last decade’s breakthrough medical procedure is next year’s malpractice. The cliché about the distinction between “five year’s experience” and a “year’s worth of experience five times” has seldom been more apt or more bitter. Then again, cultivating and harvesting one’s socio-professional network for five more years can also yield disproportionate value.

Perhaps, as some Kauffman Foundation fans have suggested, we’ll see an explosion of “silver entrepreneurship” or Tom Malone’s “e-lancing” as an industry’s most experienced practitioners launch start-ups or consulting shops to manage their transitions. Enterprise dynamics of internal competition, promotion, and mentoring will be revolutionized if the median age skews up and 60-year old executives who had planned to vanish into the Bermuda triangle of retirement in five years now push hard to stay for 10. If market forces and healthier lifestyles make 65 the new 50, then everyone now working in their 40s or 50s better revisit their most fundamental assumptions about what investing in their career should mean. When you know that being on the job 60 more months is inevitable, you have to have the courage and character to ask: How can I make them the most pleasantly and professionally productive of my life?