[animefan]

I consider myself to have a lot of mental stamina. I can focus for hours if I have to, and sometimes to job really requires it, e.g. you need to get something fixed for a customer. I don't consider this an unreasonable part of the job, but it takes a mental and physical toll that needs to be managed. As I get older (early 30's now) I expect to have less inclination and ability to do this kind of intense mental workout, and therefore move more towards management. My understand is that manual workers like builders tend to do a similar career transition.