4x10 is probably the optimal 40 hour work week - particularly if you can set it up so that you have alternating Mondays and Fridays off, such that you can get a four-day weekend half the time.
Perhaps we should realize that different people work differently, yes?
I, for one, would quit my job if I had to work 10 hours every day. I would not be able to stand it. It isn't that I don't like what I do, but I like what I do outside of work to not want to be there all the time!
From personal experience, being at work five eights vs four tens has very little impact on time away from home, like maybe one hour per day or something like that. While the five eights are sitting in their car for an extra 30 minutes during each rush hour commute, I'm sitting at my desk working. I suppose your local traffic patterns may vary.
There are downsides. Less time commuting means less time listening to audiobooks and podcasts.
Like many people, once my brain is fried I'm simply done for the day, doesn't matter if that frying happened at 9am or 7pm. So statistically a three hour staff meeting causes more total lost productivity for a ten-er than an eight-er. Scheduling people make sure meetings only happen during common time (uh, thanks?)
When the weather is bad (blizzard or whatever) or go home sick a half day, obviously that's more expensive for a tener than an eighter. Of course that is balanced out, I'm more likely to have a sick day on my weekend than an eighter and if there's a blizzard on my weekend I obviously don't miss any work.
You should consider the opportunity to have an entire uninterrupted day to pursue your hobbies, whilst most other people are at work. I found myself more personally productive on that one free day than in an entire month of 5x8-delimited evenings.
If I'm not careful, I just end up playing video games. It's hard to be aware from 'the grind' long enough for me to be drawn back into my productive hobbies en force.
