Studying strategies for a full-time working mathematician I am currently a fixed income trader and I work 10 hours a day from 5 am - 3 pm. I am a mathematician by education but unfortunately I am not doing much math and programming at my job. So, I try to study an hour during lunch and three hours after work to keep up with my skills and learn more. Specifically, I focus a lot of time in C++, computational mathematics, stochastic calculus / differential equations, and machine/deep learning as a little hobby. 

Until I find another job where I actually use my education I feel a bit frustrated with the little time I have during the week to study. On weekends I plan to devote more time to studying but I have to be realistic and relax a bit and have a life.

I guess this post is more for advice as to how I should study and gain as much time as I can to study because now I feel like I am kicking myself in the butt for not continuing my PhD and just walking away with a masters.
If you study 1+3=4 hours per day I believe this is enough. Do not worry about anything. Just keep studying like this and you will reach your goal.
(Which I suppose is to become an independent researcher)