The issue of time is not so much one of hours as one of interruptability, on the daily scale and on the life scale. I was laid off as an R&D engineer because my industry was going overseas and I was in the middle of a high risk twin pregnancy during the layoff decision making process and was not “available” for overseas trips.

Now, I have free moments during the day (like typing this comment) between getting home from story time at the library and getting the next load of laundry out of the dryer and folding it while one of my two children sleeps and the other two play.

My career is probably permanently derailed because I’m not willing to be “available”- I cannot go in to the IC fabrication facility or to Italy at any time of the day or night there is a problem, an expectation of such an engineering job.

Wal-Mart is doing the same thing- checkers are scheduled to work short shifts during the busiest times, and people who aren’t available won’t be employed.

In general, only a small portion of the workforce has control over when and how they work, due to commutes and requirements (some of which are necessary, some of which are not) of employers, customers and clients.