The cool thing is that (if you enjoy doing it, like I do) you can use the extra time to learn new and interesting skills which perhaps complement your existing skillset. I mean, you may be better served by spending time with family, or with painting or cooking or all manner of things that aren't related to work. But I really enjoy programming and 3D printing and electronics design, and with this schedule I have enough time to work on endless pointless projects which have the side effect of teaching new skills or reinforcing existing ones. This makes me more valuable than if I had stayed working 40hrs a week writing hardware test code day in and day out.