Billable hours in a freelancer's life

On the the blog Precedent: The New Rules of Law and Style, there is an interesting item showing the likely impact of "billable hours" on the lifestyles of young lawyers.We thought it would be interesting to do a variant of this for magazine freelancers. We have assumed a 5- day work week, 8 hours sleep a night and two weeks vacation.Waking hours per day 16Waking hours per work week (5 days)