A lot of people underestimate the amount of time it takes to write. When I write a story I usually do chapter lengths of around 4000 to 6000 words. Writing those alone takes several hours, constantly rereading it in the process, especially if I write them over several days. Then I reread it at least two more times, rearranging parts, trying them out at different places in the chapter, to find out where they fit best.
Once I did that I look things up on the internet I’m not one hundred percent sure of, to make sure everything is correct the way I wrote or portrayed it. That takes a lot of time too, depending on how much I need to look up.
I change words, look synonyms up and turn sentences around to try and figure out what sounds best. That takes up another couple of hours.
And then there are the hours that I spend just sitting in front of my computer staring at the page, trying to figure out how to start the new chapter, what to write. Going through previous chapters again, to make sure there are no inconsistencies and that everything still makes sense.
Reading a chapter with around 5000 words takes about thirty minutes. Writing a chapter of around 5000 words takes several days.
People tend to underestimate just how long it takes to write and how much work goes into it.