I bumped into a blog post titled "Unbounded Possibility is Bad for Productivity", a plea for setting structured limits on one's creative work. Its core advice is good and is in line with other things I've come to believe:
I've found that arbitrary deadlines, like arbitrary goals keep me motivated and focused. Without some sort of deadline or goal, I feel adrift and it's difficult to force myself to work on anything for a significant period of time. So I create artificial deadlines and goals, sometimes completely arbitrarily. Often times, I'll just pick a date on the calendar based on nothing but gut intuition, and then I change it later if necessary. ... [H]aving any sort of plan at all gives focus to your efforts and it guides you through the haze of infinite possibility. Even if your deadlines are completely arbitrary and can be changed at will, having them is the most important thing.
Selectivity is not just the essence of art, but the essence of making art. I go back to that Scorsese quote all the time, about cinema being about what's in the frame and what's out of it. It applies not just to the contents of the work, but the process of making those contents.
If I choose to work on a given project, my rough guess is that it will take me some 12-18 months to complete. This rule's been bent pretty fiercely before: Flight Of The Vajra was three years out of my life, and Welcome To The Fold took outside of 18 months because I was changing jobs and relocating cross-country at the same time.
But I try to aim for 12-18 months for a few reasons. First, and foremost, it gives me some kind of timeframe to plan around. Any timeframe, even one I end up goosing down the road, is better than a totally open-ended timeframe that imposes no urgency or constraints. Second, it forces me to confront the fact that life's short and I want to eventually finish this thing and move on to something else.
The act of setting up a deadline makes the act of moving it worth avoiding. That, in turn, gives you incentive to work on it at least a certain amount every day. How much is always going to be up to you. Not everyone wants to, or needs to, write a thousand words a day. That's my own goal, one just strenuous enough to make me put in an effort but not so much so that I can't consistently meet it.
People just getting started in some kind of creative path are not happy with the idea that a certain degree of self-imposed discipline eventually becomes needed. If you don't develop it for yourself on terms you can be comfortable with, you end up having them imposed upon you, badly, by circumstance. The way I've also put it is, "Set a price on yourself before someone else does." Find what your rules are before you end up being bound by another's.
I don't know if I'm going to finish Unmortal by the end of the year, which is the timeline I have set for myself now. Maybe I'll have to move it a little. That's fine. Just the act of telling myself "I'm trying to get it done by the end of the year" gives me a visualization of my effort. It puts into context how much time this project is likely to take before it can yield to other things. That's a huge boon when you're as compulsively lazy as I am.