I wrote such a system. 6+ years, between end of '07 to beginning of '14. It grew organically, with more and more end points as time went by, and when I exited t

I wrote such a system. 6+ years, between end of '07 to beginning of '14. It grew organically, with more and more end points as time went by, and when I exited the project it had over 250 end points, each having hundreds of thousand of users requests per day. By your measurement, that would mean the system I wrote would've handled in a month a total of 250 (end points) x 30 (days) x ~400k (requests per day) == 3B user requests in a month. To my knowledge the system is still used to this day and I think it grew 10x meanwhile, so I think it's serving over 30B requests each month. That being said, to answer your question - Yes! I got tired of it, started to plateau and felt I was lagging behind in terms of keeping up with technology around me. So I exited but at the same time I also started to get involved in other projects as well. So in the end I was overworked and I ditched the biggest project of my entire career as freelancer because payment was not worth anymore. I wanted to feel excited and the additional projects eventually made up in terms of money, but boy oh boy! the variation is what made me not feeling burnout. Nowadays if I feel another project is going that route I discuss with client to replace me with a team once I deliver the project in a stable state and for horizontal scaling.