Every now and again I run into arguments about the rigidity of time-box boundaries. Basically it goes like "But perhaps we could have finished what we wanted to do in 2 hours if we just gave it 5 minutes more. _Do we really want to discard 120 minutes worth of work just to save 5 minutes?"
You never have enough time
According to the best known of Zeno’s paradoxes Achilles (who was regarded to be the fastest runner of his time) will never be able to overtake a tortoise with a hundred step head start.
That is exactly the problem with the extension of time-boxes. Even if one would allow a maximum extension of 10% of the original time box to try to “finish it” it would likely still be unsatisfactory in the end.
Like the tortoise in the paradox (give wikipedia a short glance if you haven't already) the time “needed” for completion of the task would be extended an infinite number of times. However, after a couple of extensions, by infinitely small amounts. So in reality and for all practical purposes the timebox would last for 1,11111... times the time that was originally allotted. Which of course is a very specific time. 2 hours and 13 ⅓ Minutes if I am not mistaken.
So the point is definitely not to extend the timebox. It's got to be something diferent.
Parkinsons Law to the rescue?
“work expands so as to fill the time available for its completion”
The funny thing is, that the opposite seems to be true as well: if there only is a fixed amount of time, as soon as people realize that it is really fixed, they tend to come up with something usable in that time, effectively applying “design to budget” approaches to things like meetings as well.
And – after people get accustomed to working in timeboxes – the results usually show up shortly before the time is up.
And if they don't sticking to the timebox will help you to plan more realistically the next time around. Just don't fool yourself with 2h timeboxes that tend to last for 2:15 ... ish ...
So – just stick to the timeboxes – use them to your advantage instead of fighting them! (And remember to size them realistically!)
till next time