As a writer you are accountable to yourself and maybe to an editor. How do you keep on top of your own writing? Is it a difficult thing to do each day? Not really is my answer. You must take into account your life and the many things that pull on you each day.
Many writers have full time jobs and a family to take care of. It is not easy to write every day. I do not believe that you, as a writer, have to write every single day without fail. I think you need time for your imagination and storyline to catch up with your story. However this does not excuse you from the grind of writing on your projects. Things must get accomplished.
Be accountable to yourself as you work on your writing projects.
That is the real reason you write, for YOU.