I should actually be working 8h a day, but most of it is spend not working. If I'm honest I'm probably working more like 3h a day even though I enjoy my job.
I spend all of my day working, but the catch is that maybe only 3-5hrs a day is doing work for my clients. A lot of that 3-5 hrs is spent automating client work, so I can spend less time on it tomorrow.
The rest I work on or study whatever feels important or interesting at the moment. I'd say I spend an additional 3-6 hours a day on that. This is the secret behind always being able to say "Oh, I have a thing that works a little like that (but not very like that -- so I'll need a budget)" whenever a client wants to do something new.
Often it's little sequential puzzles I invent and then solve in my head. For example today, my goal was to find the way to take the rolling average of a certain number of bytes, with the minimum number of CPU cycles (and no 'divide' instruction). If this and 2 or 3 other puzzles have decent solutions, I'll be able to do realtime audio analysis on a cheaper and smaller chip than "should" be possible -- although I have no practical implementation in mind at this time. If it comes up one day I'll look like a real hero though, surely :D
In principle, I work 7 days a week, because I have a hard time remembering what day of the week it is. I just track the day of the month. This is much less stressful because there's always tomorrow to get something done. When I don't have "work", I just solve puzzles mentally all day or try to build random things.
I also allocate about an hour a day to answer questions on Lemmy / Reddit, mainly about engineering (I classify this as a from of "work"). That exposes me to new problems that I might not encounter in my formal workplace. Also it helps me learn to be patient with people that want to do something technical, but have varying levels of ability.
Well, there was the harrowing part in the middle where I was bankrupt in the developing world and nearly died of cholera. That wasn't a super fun few years.
...and if we're being honest, my level of obsession with engineering stuff would be considered a mental disorder, if it wasn't so productive. Like, if I had the same level of interest in 90s sitcoms instead of machine learning or assembly language, I'd surely be considered mentally ill -- but it's just one subject instead of another.
The biggest lesson I learned is to take control of my time and decide how to spend it. An 8-hour workday in a vacuum mostly gets filled with questionable tasks, it's almost like a theater filled with actors going through the motions of work, without really doing any. Life isn't too short by itself, but activities like that make it too short.
It's not something I can do for another person. You'll have to adopt yourself.