Assuming this is essentially the same as "flow" where you get lost in a task and are focused and content on nothing else but working through it, then this might be slightly dependent on motivation. I know I get burnt our on focus-intensive tasks related to work, but I am much better at staying attentive and productive (and content) longer if it's a voluntary task.
For example, doing some sort of service development and troubleshooting for something for my employer will surely burn me out if I'm doing it all day, but man I could work on my car all day no problem, or write music all day.
For example, doing some sort of service development and troubleshooting for something for my employer will surely burn me out if I'm doing it all day, but man I could work on my car all day no problem, or write music all day.