I've been an employee for like 20% of my career and a the rest I've been a freelancer.

I never worked more than 4 hours (of real work a day). There's the occasional super productive day where I have done over 8 hours of productive work, but that's the exception, not the rule.

I usually work around 3-4 hours of productive work daily. Heck I'd even say 20%-30% of that time is not even productive (meetings, emails and necessary yet unproductive things).

When I worked for companies doing 9 to 5, I wasted a looot of time doing nothing: reddit, fb, and stuff. I also recognize that I need that distraction to do some real productive work.

I'm very fast and productive when it comes to actual work, but if I don't get the procrastination time then I just become a blurry mess of a brain and take 10 times longer to do the same things.