Continuing from the last post on the Heinlein rules writers need to follow for success, let's move on to his second rule:
RULE #2: YOU MUST FINISH WHAT YOU WRITE.
To which I say, yes. But a qualified yes.
Of course you have to finish what you're working on. An unfinished story-- especially an unfinished novel-- is nigh-useless unless you get hit with exceptional circumstances*, which are not something you can count on.
But here's the ugly truth that is sometimes hard to face: not every project is worth finishing. Sometimes you're just going down a blind alley, and continuing to work on it is the equivalent of flailing around in the dark instead of finding a light.
So here's the qualification: You must finish what you write, unless you determine that finishing it wasting your time.
HOWEVER, "wasting your time" is a LOT different from, "This is hard and I want to work on the shiny new thing I came up with". Like I said last time, write with discipline, and that means pushing through the hard work to the other side. And every one of the finished projects that I have shopping had that fallow period were the process of writing felt interminable.
There's a difference between smashing your way through the brick wall, and smashing your head against it. The really hard part is figuring out which one you're doing.
And most important, if you don't finish one thing that you write, you're not finishing that so you can finish something else. Because, yes, you must finish before you can move on to the next step.
*- For example, Scott Lynch sold Lies of Locke Lamora on the strength of excerpts of the unfinished novel he had posted online, mostly for the purpose of having friends give feedback. But because of a friend of a friend, that led to it getting the attention of a publisher. However, this was a lightning-strike confluence of luck and talent, and should not be one's battle plan.