Are you serious about writing if you're not writing daily?
Many people insist you have to set a goal of so many pages, words, or hours every day. I admire those who have full time jobs and manage to get up before dawn and work a few hours every single day. The stamina of people who take years to finish a first draft a few pages at a time floors me.
I am a project-based worker. I can maintain a regular writing routine for a defined amount of time. For instance, the when I was writing the first draft of Tough Times (at that point called Michael Dolan McCarthy after the main character), I wanted the manuscript ready to submit to a particular contest. I stayed at a condo in Angel Camp for two weeks and set my goal at 10,000 words per day minimum to finish the first draft. My daily structure also included catching up by reading a stack of professional writing magazines and walking outside. The first draft was sent to beta readers and revisions were made in time for regular entry into the contest, where it made it to the quarter-finals. However, when I'm not working on a specific project with a specific deadline, I have many other interests and responsibilities that keep me busy - until I sit down to write. Then time disappears and I keep going until something is complete.
Imagine my relief when I read Stephen King saying"Once I start work on a project, I don't stop and I don't slow down unless I absolutely have to...And when I'm not working, I'm not working at all... For me, not working is the real work." (P. 153, On Writing: A Memoir of the Craft). He's a project-based worker, too!
He does recommend having a daily goal when you sit down to write. Currently, I'm working with a group from WNBA (Women's National Book Association, not basketball) where we set goals and hold each other accountable. I'm working on revising a novel written several decades ago. I want it done by the end of March to swap beta reads with a fellow author. So, my goal is to write at least eight days and finish at least twenty pages each of those days. My first day, I polished the first twenty-seven pages. The second, I revised and tightened another twenty-two. Some pages are ready for critique by the local writers group; others are ready for my online group. I won't have a chance to lose myself in the writing for a few days - I have other obligations on three days and will try to do all the odds and ends of things those days, so when I hit another writing day, I'll be clear to do more than my minimum goal.
So while writing daily may be best for some, others may have different patterns that work as well. The key is setting goals and giving yourself time to meet them.