I keep track of how much time I spend doing intellectual labor. It works out to 60% of my free time and 49 hours per week. I also separate my labor into two categories: hard and easy. The hard category comes to 43 hours per week since last April. That includes computer coding and writing up paper solutions which I will eventually code into a computer. I'm building an automated theorem prover and it's very hard. What bugs me however is that I cannot average more than 43 hours per week. It should be 60 hours per week and 80% of my free time. I try to work on this automated theorem prover as much as possible but my brain gets burned out way too much. It would be some consolation if I knew that other people have the same problem.