What if you work 16 hours a day because your current employer is highly dysfunctional and you are constantly putting in hail mary efforts to save them from themselves?
How is one supposed to have time for side projects then?
Most sane folks would like to find another job to quit into rather than just leave their job, but if you have a great financial cushion to rest on, sure, go ahead.
Having been poor most of my life and worked full-time since I was 15 years old (with an odd break or two), I can tell you that that is a luxury most people do not have.
Don't quit a job until you have another -- and actually being currently employed is like free bonus points when interviewing.
Have you heard the expression work smarter not harder? You're working 16 hour days likely for the income of a regular 8 hour day -- so you're literally making half the salary you think you are. That's not smart.
Some crunch time is normal and if you're lucky, compensated for. If I'm working all out weekends to finish a project (might happen this month for me) then damn straight I'm taking some days off in lieu for that when things calm down. If it never ends, that's not crunch time.
How is one supposed to have time for side projects then?