Break-even spending rate

Via Quora:

"A better model would be the break-even spending rate, defined as the salary earned divided by the amount of free time.  Another way to think about this is the amount of money one needs to spend per hour to have zero savings.  Assuming you sleep 8 hours per day and spend 1 hour per day on basic needs, there are 105 hours left per week to divvy up between work and free time.  If you work 40 hours a week for $30 / hour (so $1200 per week), your break-even spending rate is $18.50 per hour.  It goes up to about $26.50 if you work 60 hours per week and $48 if you work 80 hours per week, though I'd expect an investment banker working 80 hours per week to be earning significantly more."