Oops! My bad! I just realized that you're talking about a different book. I thought you were referring to the book's namesake, Polya's "How to Solve it." I have not had any contact with how "How to Prove it"!
Also, interesting how much of a similar way we seem to have gone about learning math. I kept it as my main focus for a similar amount of time, then for as a secondary focus while working on a big software side project for another 7 months or so (I was working at a grocery store for money the whole time), then got my first software engineering job and largely dropped any focused study in mathematics. But now I'm in a position where I'll learn bits of math as I need them for projects or whatever, so it definitely wasn't a waste (and like you mentioned in being able to read stuff off of arxiv, it expanded the range of ideas I can understand).
I've actually started getting interested in continuing study again, getting more into applied math this time since I really focused on pure last time. First goal is to get a clear understanding of Maxwell's Equations :)
Also, interesting how much of a similar way we seem to have gone about learning math. I kept it as my main focus for a similar amount of time, then for as a secondary focus while working on a big software side project for another 7 months or so (I was working at a grocery store for money the whole time), then got my first software engineering job and largely dropped any focused study in mathematics. But now I'm in a position where I'll learn bits of math as I need them for projects or whatever, so it definitely wasn't a waste (and like you mentioned in being able to read stuff off of arxiv, it expanded the range of ideas I can understand).
I've actually started getting interested in continuing study again, getting more into applied math this time since I really focused on pure last time. First goal is to get a clear understanding of Maxwell's Equations :)