If you're good enough then volunteer or hire yourself as a tutor or night college teacher. Also, there are a number of people that produce calculus tutoring yo

If you're good enough then volunteer or hire yourself as a tutor or night college teacher. Also, there are a number of people that produce calculus tutoring youtube videos. Maybe you can try that. Unfortunately, a large percent of what we learn will eventually be forgotten due to lack of use. Most of what we learn will not be used at work. I remember spending tons of time studying calculus yet I've yet to use any of it. If ever I need to use it I will need to review it to refresh my mind but most likely I won't remember most of it.