Over the last 12 years I have been at my current job, I have probably barely averaged 30 hours a week. What's good is the way my salary works is I get 40 hours pay, except if I work over 40 hours then its overtime. Really beneficial for myself.
The way my work is as an engineer, I basically babysit the equipment (flight simulator) and wait for it to go wrong, if it doesn't go wrong and they finish using it we go home. A few years ago I had it for 4 months were I had 1 week in 3 completely off

. Take this week for example, I didn't go in on Monday, Wednesday and today and did approx 3 hours total in the other 2 days.
My hours are stupid but in a good way