Bozo (unique name),
First, my understanding of auto salesmen, is they work pretty long hours.
Also, I live in Japan, so I know what the meaning of "Monday, Tuesday, Wednesday, Thursday, Friday, Friday, Saturday, Monday" is!
Though I don't work Sundays, I get a pretty good share of Saturdays! It was worse about 5 years back, when I'd return home late, around 11pm, and get up (on my own, without the help of the "then wife") at 5:30 am to do it all over, again. Fortunately, I enjoyed the job, so it wasn't so obvious how exhausting it was. After a while, the job lost it's "spunk", and I started feeling the repurcussions of it.
I am 40, so I was turning 38 when it happened. If your health is pretty good at 38, I highly recommend you do something to relax, cut down stress, and find some time for yourself to enjoy, AND to take care of your health! I had to learn that part, the hard way. After working so hard for the company and ignoring my necessities for a healthier me, my production level was becoming inefficient.
If work hours can't be cut, is it possible to take more holidays? (similar to what SeanDavis may see?)
Good luck!