Sustainable Pace

February 29th, 2012

What is Sustainable Pace?

Sustainable Pace is an essential part of both Extreme Programming and the Agile Manifesto. In contrast to aspects like Test-Driven Development or Continuous Integration, Sustainable Pace is less known, less formalized, and thus is often perceived as fuzzy or diffuse.


The concept behind Sustainable Pace had been discussed in the aftermath of the creation of the Agile Manifesto in 2001. The foundation had been established by XP guru Kent Beck in the first edition of "Extreme Programming Explained" (1999), where he suggested working no more than 40 hours a week, and never working overtime a second week in a row. With the "Eight Hour Burn", software craftsman Robert C. Martin focused more on the energy aspect than on time alone, which led Ron Jeffries to call the practice "Sustainable Pace", and not "40 Hour Week".

Finally, one of the principles behind the Agile Manifesto was dedicated to "Sustainable Pace", which can be regarded as the most widely accepted definition:

Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.

Later that year, Alistair Cockburn noted the manifesto authors were motivated to discuss Sustainable Pace both because of the project effectiveness and the social responsibility side, with a strong focus on the former.


Back in the 1920s, Henry Ford proved that productivity is not increased by work time, he found he made the largest profits with labourers working 40 hour weeks. It's interesting to note that most laws, like the EU working time directive (work no longer than 48 hours per week), are not only influenced by social responsibility, but rather productivity concerns. However, as a german study from 2011 suggests, still one in six university graduates works longer than 48 hours.

What happens if software development occurs during overtime? Several studies show a productivity boost in the first week of overtime, with productivity decreasing rapidly and ultimately falling below the productivity level of the 40 hour standard. During overtime, people fail to notice a drop in their cognitive abilities, resulting in mistakes and finally quality degradation. The difference in quality is referred to as "technical debt". Martin Fowler translated the metaphor to software development,

Just as a business incurs some debt to take advantage of a market opportunity developers may incur technical debt to hit an important deadline.

and Ward Cunningham, who coined the debt metaphor in 1992, elaborated

Every minute spent on not-quite-right code counts as interest on that debt

In system theory, the accumulation of technical debt due to overtime could be described by the "shifting the burden" archetype.

Sustainable Pace

Scheduled overtime, as a main source for technical debt, should be avoided, and if technical debt occurs, it should be addressed as soon as possible, in order to work in a more predictable, more balanced system.

In 2004, Kent Beck revised "Extreme Programming Explained", and replaced the "40 Hour Week" with the concept of "Energized Work":

Work only as many hours as you can be productive and only as many hours as you can sustain.

This change did not go unnoticed, as Software Kanban guru David J. Anderson described his perception of that paradigm shift. Being influenced by the book "The power of full engagement" by sport scientists Loehr and Schwartz, he describes how his view on large scale software development changed, he no longer regarded it as a marathon, but a series of short sprints, where energy is expended vigourously and restored during pauses. He also mentions favouring rituals over self-discipline.

Concepts that combine both the sprint and the ritual aspects are the Pomodoro Technique and Slack.

Work should not happen at a strictly constant pace, but more dynamically by expending energy and restoring it, making use of rituals.


Happiness research teaches us that income and happiness only correlate up to a certain point. There must be other aspects beyond financial success that increase happiness. Bruno Frey introduced the term procedural utility, which states that happiness cannot be achieved directly, it is more like a byproduct. In self-organizing teams, like in Scrum, people feel more competent, related and autonomous, which are three main sources of procedural utility. The New Economics Foundation has also dealt with the findings of happiness research, digesting it into the Five ways to well-being.


Sustainable Pace is not about taking it easy and going slow. It's just the opposite, you should expend energy vigourously, and regain strength by resting. In the long run, make sure you invest your energy wisely, and set your priorities taking into account the findings of happiness research.

As stated in Bronnie Ware's The Five Regrets Of The Dying, having worked too hard is something especially males regret at the end of their lives. We should not work for the purpose of being successful and happy later on, but focus on well-being now. It should be the measure for success and a starting point for meaningful work.