Productivity, like religion, is a concept prone to much interpretation. All of us bring our own biases to the table.

The commandments all have their place. But as I’ve been interviewing people for this project, and thinking about how to make my work hours more “productive,” I’ve realized that many of these bits of wisdom don’t have a lot to do with my life. For starters, most assume a corporate office culture.

This is the 168 Hours principle for work: Ideally, there should be almost nothing during your work hours—whatever you choose those to be—that is not advancing you toward your goals for the career and life you want.

Any “work” that is not advancing you toward the professional life you want should not count as work. It is wasted time.

Part of being effective during the hours you choose to work is developing the discipline to spend real time on what’s important even if other things—including, frequently, your own bad habits—try to shove you off course.

If you adopt this philosophy, look objectively at your schedule, and are honest about how much time projects will take, I’m betting you can find space for almost anything that matters to you within your 168 hours.

But once you start breaking commitments to yourself and the people around you, the whole system of discipline—the trust you build up in yourself to be in control of things—breaks down. Again, the world is not going to make it easy for you to stick to your priorities. Don’t let your own weakness contribute to the problem.