I make a point of getting regular rest days with hardly anything physical happening at all. When I get tired, things I do start blowing up in my face, costly mistakes and that sort of stuff.

When I get a little extra rest, I usually find I needed it more than I realized. Just lately with a health problem, I had the nicest improvement on a 3 day break. On the second and third days, I fell asleep at least 3 times each day, during the day. It's easy to get a bit stressed out at work without realizing it.

Rest is a priority for me.