Fitts™ Law to calculate the expected motor movement

For UX pros, how often do you use Fitts’ Law[SIZE=14px] to calculate the expected motor movement? I’m stuck with one of the quizzes at Coursera, which made me curious about how often this formula is actually used. Any info would be greatly appreciated.[/SIZE]

Funny, I just got to this part of the Coursera course and went a-Googling for Fitts Law, and found this thread. I’ve been working in UX for about 10 years and have never come across it in a work context.

That’s what I thought. It was easy to figure out once I re-learned how to use my scientific calculator, but I didn’t see the relevance value of that lesson.