I can’t call myself entirely self-taught, since I had a couple years of college, but I’ll share my career perspective anyway.
I have no concept of how much time I spent at it, other than “too damn much of my life”: programming was always a hobby for me, starting with BASIC on my Commodore 64, and I’ve continued it since, though perhaps a little less zealously than I once did.
Other than toying around with Forth a bit, I pretty much stuck with BASIC until college, never building much that was interesting: I did type in a lot of programs from Compute! magazine back in the day though. Once I got to college, while I was getting an education in fundamentals like big-O notation and discrete maths, I also taught myself C and C++.
After college, I went into my “larval stage” of programming, hacking all day and night, mostly on programmable MUDs. I built a few fun projects on those too, mostly in the guts of the MUD like command parsers, but also a few cool toys like a Go board.
I eventually got my first tech job at Xerox testing their top-end printers. Basically my job was to print out reams and reams of paper worth of test prints every day, flip through them, and look for blank pages. Whee. In my spare time, I fiddled with Postscript to make my own print jobs (that Forth background was a big help), as well as printed myself out a bookshelf’s worth of nicely covered and bound UNIX manuals for everything I was interested in, like sendmail and perl.
Anyways, more years, more jobs, already turning into a long story. I didn’t pick up a “real” programming job til years later, but the overall pattern is that I always picked up side projects at work, authorized or not. These projects would always be some small little improvement for what I was working on: a clipboard agent for popping open tech support tickets copied from a report. A web UI for reporting on another ticket tracking system. My favorite was a data acquisition and view system for a bunch of Trans-Lux DataWalls. You haven’t lived until you’ve written a device driver in perl.
My first job as an actual bona-fide programmer didn’t happen until I was some eight years out of college, when I got a job programming backend website functionality (again in perl) mostly for things like multi-step form validation. Boring stuff, but I made it somewhat fun by inventing a clever (at least I thought so then) library to handle a lot of it. My longest job as a programmer grew out of side projects I wrote to make my job as an anti-spam technician easier. By then I’d been studying many different programming languages, and I ended up writing projects in perl, python, emacs lisp, javascript, java, scala, C++ and even took a stab at Haskell here and there. It was fun.
So basically I muddled through without a plan or direction, and it worked for me nonetheless. I am now back to programming websites (full-stack now) for a tiny outfit of less than a dozen. Making half of what I could, and writing in PHP at that (a language I detest). So not a world-shaking success story, but ultimately I’m happy to be out of the Fortune 500 corporate environment and being allowed to continue experimenting and having fun.
That last word, “fun”, is one I throw around a lot for a reason. I’m not going to say you can’t succeed in a programming career if you treat it as A Serious Job You Must Seriously Study For, but for me the main driver is enjoyment. I have to enjoy making a creative solution from nothing, or taking what’s already there and making it better. I can’t always have fun programming (especially in PHP) but if I can take my experience and theory knowledge and come up with something powerful and elegant, it makes my day and keeps me going.
So I’d say the primary resource I tapped then and continue to rely on now is Fun. Good thing it’s a renewable resource.