If you mean "gaps in my education" or "basic things that I don't quite understand", you could try studying some high-quality texts. Look for books written by extremely smart people who are trying to explain the ideas rather than taking you through the standard topics. Hamming's books on probability and signal processing and Strang's books on linear algebra and applied math come to mind.
Alternatively if you're really interested in intuition, you could also look at the Math Olympiads. Pick a problem, beat your head on it, finally look at the solution, repeat. There are web sites and prep books.
At the high school and college level, the Olympiads for math and CS are pretty analogous. But there's really popular semi-formal coding contests which exist outside academia which don't really have a math equivalent.
I'd say math contests are more popular among high schoolers, and semi-formal coding contests more popular among college students.
Art of Problem Solving (AoPS) [https://artofproblemsolving.com/] is a really good resource, and there's a very healthy online community.
They're also similar in how olympiads are different from the "real thing" (TM).
As someone who did math olympiads in high school, my 2 cents is that they're a fantastic way to learn how to solve and approach problems and gain intuition. And I'd say intuition mainly comes from solving problems.
Not just nylon ropes, but multi-fall ropes: in the early 70's, we didn't trust a rope after it had taken a hard fall. You can't learn a big-wall route if you have to retire your rope after every long fall.
From personal experience, I can tell you that $6K/month is not exclusively a Silicon-Valley phenomenon.
Basically you cover it with whatever SS, pension, savings, and other assets they have. When those don't cover it, you make compromises in quality of care, your finances, and your family's life.
