A dear friend and fellow author, Dana Eilers, recently complimented me for being so disciplined in my writing, since I write each day. The comment took me by surprise, since I do not think of myself as disciplined. But, I am fortunate to have the time to devote to writing at the present.
I know I am more productive in the evenings, for writing, and more productive during the day for research, editing, and proofing. So, I guess I do follow a schedule of sorts. During the day, I research any plot points that need to be resolved, I proof what I wrote the evening before, and do necessary edits. Sometimes I write, sometimes I don't.
In the evenings, I turn on my favourite radio station and let the words rip. Sometimes I may not write too much because I get hung up on a particular scene or chapter. Sometimes I write 1200 words without batting an eye. So, my output changes each day. And, sometimes I write crap that just needs to be tossed in the trash and I start all over again.
My schedule works for me because I know my best times to write and because I do it each day. Your schedule works for you -- it could be every day, or once a week, but it's yours. Writing should be a pleasure, not a chore. Once it becomes too much of a chore, your writing will suffer. But, you should find a schedule that is right for you and then stick to it. You will find your work will improve and so will your output.