The way I see it is that every writing advice out there homes in on the following mantra: write every day, no matter what. Some, like Stephen King in On Writing, even suggest that you will never really get anywhere unless you write a few thousand words a day.
I partially agree with this advice. I do believe in steady writing. Also, I think that if I were to write only 250 words a day, it will take me an awful lot of time to finish my novel. And what about all the other ideas in my head?
Steady, sustainable writing though is the crux for me here. What is the point of writing 1500 words today if this would drain all creative reserves for tomorrow? Figuring out what is a comfortable daily or weekly writing goal is perhaps a better approach than aiming for a set word count. I’ve experienced that overstepping my comfortable limit is counterproductive to good, steady writing. And even worse, it leads to less and less writing.
I usually work on a single long-term project at a time. On such projects, I write on average 1000 to 1300 words a day, 4-5 times a week. I work on other shorter projects sporadically. This is my comfortable limit and it has steadily been increasing. I started out with 500 words or less a day. What got it better, I believe, is that I have been harvesting my creative pool rather than draining it.
So, no matter what best writing practices recommend, in my opinion, the most important thing is to find a way to keep writing, page after page, day after day.