[BWStearns]

a) Why is 40 hours the magic number and not more or less?

b) Isn't the 40 hour work week pretty much a relic of industrial development? What about 40 means "virtuous"?

[vinceguidry]

Nothing magic about the number. You could probably do the job in much fewer hours if you're very focused. But I find it hard to maintain that level of focus for a significant period of time.

But you definitely don't need more.