I started writing a book 2&1/2 years ago. I got 70,000 words in to it, and wrote a very emotional chapter. So emotional, in fact, that I had to stop. I doubted my ability, and my right, to write something so emotional about something I have no experience with. Two months ago, I resumed, and finished the first draft with over 200,000 words. I'm halfway through second draft edits and additions.
For the 2+ years I spent not writing, I constantly thought of ideas, and I now have rough sketches for two sequels. But my intention is it write both sequels, each possibly exceeding 200,000 words each, before I even attempt to get published. As I write, the story changes, and I want the tale to complete. I don't want to change my mind about something, only for it to be too late to change. So I work at editing volume one, knowing that it will be ages before I finish.
I'm not writing to publish. I'm writing to get the story out of my head. But its addictive. Not only do I have the two sequels planned, but I've had rough ideas for three different prequel trilogies. That's nine more books, although each nowhere near the length of the primary books. And I've got a completely separate series in mind, which would span 5 stories.
I'm afraid that it will never end. Or worse, I'll finish, only to be told it's not good enough. I have no-one in my life that would be a beta reader for the story, so I have no concept of how others would feel about the work. I have friends and family that could read it, but the subject matter isn't something they'd be interested in. For all I know, I could write 600,000 words (mostly consisting of 'uh' and 'um') and finally send it off, only to be told that its not worthy.
So I'll write it for me, and take solace in the fact that it's good enough for its intended audience.