I was a promising grad student for 5 years and got sidetracked by the 60's.
(at first i had a no - teaching fellowship, then got a TA. after a while I unloaded meat as a side job, but had no family then to support.)
the last couple years i essentially forgot what i had learned the first three, as the world got more chaotic and i lost focus.
then I left school and began teaching with the masters degree i got as an exit prize from the phd program, and started a family.
then the school where i taught said they would terminate me if i did not get a phd. this was a catch 22 since i was already considered one of the most well educated people at that school, so a strong phd would "overqualify" me essentially.
but what to do, i prepared as hard as i could, then took my wife and child and called around for some recommendations.
there is always a shortage of "promising" grad students so a prof from my old school recommended me to his new school and they took me on probation sort of, i.e. with a short time frame, expectation: 2 years to degree.
i worked hard and learned a lot but after 2 years was not done, so they gave me one more year to finish. i got lucky, found a helpful advisor and made a nice discovery. then i got 3 job offers (not including my previous teaching job), nsf postdoc, ... and never looked back.
the alternative to becoming a professor with travel and research options would have been returning to that teaching college with no other options or chance to ever get out of there, or do any real math.
i.e. in spite of my lack of appreciation for it in advance, the phd experience did raise my math knowledge and research ability to a higher level. it gave me the experience of actually doing and not just learning math.
math to me now is a subject with its own existence, its own identity, not just a bunch of rules on a page written by someone else.
now i can read what someone else has written about an elementary topic and ask whether it should have been done that way. i am not bound to memorize the way the author did it.
of course everyone has a different opinion about this, but at least i also have one now based on my own experience in the world of doing math.
actually i may not have made as much money as i would have by staying at that other job (had it worked out), but mathematically i have had more fun and met more people.
i have tended to make choices based on increased educational opportunity for me and my family, rather than wealth, but that has caused problems. i.e. tuition costs money too.
it is not a problem to a single guy because almost any school will offer marginal support to a dedicated and capable student.
yes i am a riemann surfaces, and abelian varieties specialist. i am amazed at how little i still know about them though.
