As a former mathematician and current dev, they are different environments. In software engineering, 60+ hours a week on just work stuff is bad...I've noticed

As a former mathematician and current dev, they are different environments. In software engineering, 60+ hours a week on just work stuff is bad...I've noticed a bit of performance degradation at around 50 hours. I do spend a large amount of out of work hours learning more stuff on my own, but mentally it's a different ballgame, which lets you be more relaxed. In mathematics, your mind is mostly in the relaxed state, unless you're about to take an important exam. For the process of research, you just spend the time you can delving into a particular topic and understanding it. The life of a mathematician is more analogous to learning & experimemting with different code libraries on the side. The mental balance errs more towards relaxed experimentation as opposed to just getting it done.