What will you choose to fail at? This surprisingly powerful question comes from Oliver Burkeman, author of the new bestseller Four Thousand Weeks: Time Management for Mortals. Burkeman makes the grim but useful observation that human life expectancy of about 77 years adds up to roughly 4,000 weeks. That's just not enough time to do everything that we want or hope to do.

The sooner we accept this reality, the better off we'll be, he told Inc.com in an interview. "It's not about finding the tool or philosophy or amazing level of self-discipline that will allow you to finally make time for everything," he said. "That's flawed almost on a mathematical basis. We live in a world of infinite inputs--emails, work, demands from the boss or the small business you want to launch, family obligations, bucket list destinations. There's no end to any of those. We have the capacity to imagine infinite possibilities. Yet here we are with roughly 4,000 weeks of time."

Burkeman disdains the commonly offered advice to eliminate everything that doesn't matter so you have time for everything that does. "There's no particular reason to assume that's going to work," he said. "There are only going to be so many things that matter that you've got time for."

This is the thinking behind what he calls strategic underachievement, which he describes as "nominating in advance whole areas of life in which you won't expect excellence of yourself." One obvious advantage to this approach is that it will help you use your time and energy most effectively for the things that matter most, because you'll stop spending them--or stop spending more than the bare minimum--in areas where you've already decided to fail.

Another, less obvious advantage, is that you'll be happier, because you can stop feeling ashamed about those failures. "A poorly kept lawn or a cluttered kitchen are less troubling when you've preselected 'lawn care' or 'kitchen tidiness' as goals to which you'll devote zero energy," Burkeman explains in his book. (Since I have both a poorly kept lawn and a cluttered kitchen, this advice sounds great to me.)

A failure at cooking.

Burkeman says he himself has chosen things to fail at. "This is a silly example, but I really would like to be a good cook," he said. "I'm endlessly displeased by the things I end up cooking when it's my turn to make dinner." But four years ago, when his son was a newborn and he was starting work on Four Thousand Weeks, he decided he wasn't going to improve his culinary skills anytime soon. "It was clear what my biggest priorities were," he said. "Cooking was something to consciously jettison."

In this way, he said, realizing how few weeks you have can be uplifting rather than depressing. "It's actually liberating and empowering to see that so many of us have been fighting an impossible battle to get on top of everything and be in command of time," he said. "The attempts to do everything generate even more things to do and even more anxiety. The way to get off that treadmill is to glimpse, at least a little bit, that you're never going to achieve it. Then it becomes a lot easier to stop trying." Once we stop trying, he said, "We can start using the time we have in the most fruitful way."

What will you choose to fail at? And where will you choose to focus your attention so that you can succeed?