I have been working as a professional software developer for 12 years and I have a B.S. in Computer Science. I've primarily been a full stack web developer. I have read multiple accounts of programmers being stressed out and/or having too much work. I find myself an oddball in our industry because it's been the polar opposite for me. I have experienced low work demand/lots of downtime at multiple different companies.
How do I avoid excess downtime/low work demand? I'm interested in general answers, not specifically related to programming.