As craftsmen, we admire and encourage a sustainable pace. We also encourage ourselves to always be learning, to always be expanding our knowledge and abilities.
There is an interesting cross section between these two principles that I've discovered over the past few years. Once, maybe twice a year I find myself approaching a deadline and I need to put in extra hours over the course of 2-3 weeks in order to reach the project goals. This push toward the finish can be exhausting, but it can also be an incredible growing experience, one that you don't get by always working 40 hours a week.
Prerequisites
A prerequisite for this "overtime" effort is that the goal must be clearly defined. The stories are clear, the acceptance criteria has been vetted, and everyone knows their responsibilities. It is also somewhere between 25-50% beyond your normal capacity, not more (if you work 40 hours a week, jump to between 50-60 hours). All of these things must, must, must be true.
When Things Go Well
Let's assume you've met the prerequisites. Over this period of time, you get a chance to:
Push The Limits of Your Stamina
Before I began my apprenticeship at 8th Light, I thought I had an idea of how much I could really learn over a period of time. I could attend a training for a week at 8 hours a day and feel OK at the end of it, or spend up to 12 hours at a time deeply engaged in solving complex problems and still be functional the next day. After these bursts of effort, though, I knew I needed to back off and slow it down.
During my apprenticeship, though, I spent long days trying to learn as much as I could about test driven development, design patterns, new languages, new technologies, etc. etc. There were slower days as well, but this consistent interval-style training over a period of months was paying off. I was spending far more time on focused learning AND complex problem solving than I would have thought possible when I started.
As a craftsman, I've found that by increasing my effort over a short period of time, I get a sense for what 100% of my effort really is. Also as a craftsman, it's important to be careful - as an apprentice only my learning was affected if I went overboard, but I owe it to my client as a professional not to drop in productivity.
Learn Quickly
With a period of intense focus, I also get a chance to learn a lot very quickly. Getting more done in a few weeks means feedback loops are shorter and more frequent.
Working under pressure can also be inspirational, in a way. Rather than thinking I can put off learning something until later, I am forced to learn it now in order to get the job done well. After finishing, it can be surprising to realize how much knowledge and experience I've gained in a short period of time.
Test Your Dedication to Your Principles
Extra hours means the pressure to get things done increases. The question of what is really important to completing the feature starts buzzing in the back of your mind - do I need a test for this? Should I just refactor later? Can I just pay down this technical debt sometime in the future?
While I like to think I'll follow my principles when things get tough, there's only one way to really find out if that's true or not.
When Things Don't Go Well
Those prerequisites I mentioned? Well, more than once I've ignored my own advice, and every time it's been flat out miserable. I spend so many hours trying to get everything done, but I don't know what done is, and the end result is a "failure". I feel burned out and demotivated, which means I'm less effective going forward (compounding the other problems that got me into working overtime in the first place).
Additionally - even if I am following my principles when working overtime, I've already sacrificed one of them by not being honest about the situation and the possible outcomes.
Stretch your Limits, Carefully
When working extra, you run the risk of burnout. It's important to recognize when you're reaching your limits, and to back off accordingly - a bad case of burnout can leave you demotivated for months, even years.
Still, increasing your workload once or twice a year can greatly accelerate your progress towards mastery and leave you surprised at your capabilities. Just be careful to do it at a sustainable pace, and make them even more effective by avoiding the bad ones entirely.