Flexibility is the key. One size does not fit all.

I worked a Mon 13, Tue 13, Thur 14 for a while and it was a great schedule. My job was 'white collar', not sure that I would want to work days that long if I were in construction, but....

After most folks went home at 5 I was able to be much more productive. The phone wasn't ringing, people weren't stopping by the office to shoot the breeze....

Had Wednesday to get the chores done and a three day weekend every week.

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One place that a 3 or 4 day would really improve things is here in the mountains where the Cal Trans crews come out to work on the roads.

They work an 8 hour day. It's about 10am by the time they load up and drive to the site, 10:30 by the time they get the flag stops set up.

They break at 12:00 for lunch. And start packing up to go home about 3:30.

Roughly four hours of paid "work" time on the road each day. One hour setting up, taking down.

Leaves three hours for work. (Fifteen hours out of forty.)

One less work day would add four hours of productivity.

I've worked odd hours sometimes. Some things I loved, some things I didn't. I used to work a night shift at a deli. It was nice to do my shopping at 2 am when there were no crowds around, and to have the days free. OTOH, it was a real drag on my social life, since all my friends socialized in the evenings, while I was at work.

I sometimes work evenings and weekends, and I like the peace of a quiet office. But there are drawbacks. If the network goes down, there's no one to fix it. And the building is often physically uncomfortable, since they turn off the heat/air conditioning outside regular work hours. There are also security issues, like the superior with a drinking problem came in late in order to grope me, knowing I would be alone.

How long is a "ten-hour-day" when you add on an unpaid lunch (lunch is not required to be compensated under Federal Law) and commute times? 11 hours? 12?

This is a terrible idea for lots of workers, especially parents, and laborers, and the physically weakend.