In my last article, “Packing life’s suitcase,” I suggested that people should plan at least one week in advance. I did not say we should ignore the weeks beyond that, since God willing, we will still be active and motivated to achieve great things well into the future. But the farther you plan in the future the greater the likelihood that you will have to change some of those plans. Priorities can change quickly these days.

Things that you should record in your planner weeks and months in advance are those repetitive priorities that must be done daily, weekly or monthly. These could include such things as business meetings, conferences or personal activities such as doctor’s appointments and vacations. By doing so, you not only can’t forget them, you also have a better idea of the actual time you will still have available for those urgent items and additional priorities that invariably occur in the future.

These repetitive priorities should also include those goal-oriented priorities that you have decided to complete during the year. For example, I schedule one or more 90- minute blocks of time each week to work on my latest book. This time is treated as though it were scheduled surgery or a 90-minute workshop for a major client. It’s very unlikely to be displaced since the only thing qualified to replace it is an even more important priority.

During these 90-minute work sessions your iPhone should be on airplane mode, your landline with voicemail engaged, your email ignored, and if possible, your door closed. The world can survive for 90 minutes without you. Immediately following your 90-minute work session your planner should be blank for at least 20 minutes. This is break time, email time, call-back time, or simply “walking around your desk” time. Marathon work sessions beyond 90 minutes cause a decrease in productivity and energy level.

The next scheduled block of time, whether a half hour or 90 minutes, would ideally involve a completely different type of work to give that part of your brain a rest. For example, if you just finished writing for 90 minutes, switch to more physical work such as getting all the materials together for your next meeting. You can also have that performance review session with your administrative assistant – anything if it is essential and involves a different type of activity.

Don’t forget your coffee breaks or stretches. Every 90 minutes or so you should get up and move around. Tom Rath, in his book Eat Move Sleep, called sitting “the most underrated health threat of modern times.” He claims that sitting more than six hours a day greatly increases your risk of an early death. (Following 8800 adults for seven years, it was found that those sitting over four hours a day watching TV had a 46% increase in deaths from any cause when compared with those who sat in front of the TV set for less than two hours a day.)

Even if you only had one large task to complete, such as write a book on your industry, it would still be more effective to work at it in chunks for 90 minutes than to work at it steadily from 9 am to 5 pm every day. You are justified in engaging your voice mail and ignoring your email for 90-minute stretches, but not for 8-hour stretches.  People may wait two hours for you to return their calls, but rarely eight hours.

With shorter work sessions you would also have fewer self-interruptions.  Have you ever tried writing for 8 hours – even with a lunch break?  I have, and before long I was looking for interruptions. If we work too long at one time our ability to focus weakens, we daydream, go on little mental excursions and are more easily distracted as our energy decreases.

When confronted with an “overwhelming task” such as writing a book, most of us tend to procrastinate.  Breaking the task into smaller chunks of time is a great way to overcome procrastination – even if those chunks are only separated by 15-minute breaks.  That way we are only committing ourselves to 90 minutes at a time.

To summarize the advantages of working in 90-minute segments of time: Energy & ability to focus rises & falls in 90-minute cycles. 90 minutes is about the maximum time that most people can concentrate on a task. 90 minutes is usually an acceptable time to be unavailable to others. 90 minutes allows “prime time” for at least two projects each day. And 90 minutes is the minimum work period before “make ready” starts having a significant impact on your efficiency.

In the next article I will offer some additional suggestions for planning your week.