Bill Mullins writes on the subject of writing…
Robert A. Heinlein had five rules for writing:
- You must write.
- You must finish what you write.
- You must refrain from rewriting, except to editorial order.
- You must put the work on the market.
- You must keep the work on the market until it is sold.
He was coming from the perspective of one who wrote and sold fiction to magazines, so the rules may not be quite so applicable to script writers or joke writers. But note Rule 2: "You must finish what you write."
So the answer to your question, "If you spend six hours writing something and you're halfway through and it ain't going in a good direction, why spend another six hours completing it?" can be found by placing Rule 2 in the context of the other four rules. You have to finish it because you can't sell it otherwise. An artistically unsatisfying work that is complete may sell to some editor somewhere. But a half-finished piece won't sell anywhere.
I feel odd just typing the words, "I disagree with Robert Heinlein" but I disagree with Robert Heinlein…a little. And I don't think the differences are due to him writing for different markets.
Yes, you must write. Yes, you must finish things but you don't have to finish everything you start. I seriously doubt Mr. Heinlein ever wrote the first few paragraphs of a story, realized it wasn't going anywhere but thought, "Rats! My premise isn't very sound but since I started this thing, I have to finish it." Even a man as clever as Robert Heinlein was has some ideas that are better than others and there's no shame in pitching the weaker ones.
So I agree with #1 and I think #2 should read, "You must produce a decent amount of finished, ready-to-sell material" or words to that effect.
In #3, I suspect what he meant is that you shouldn't keep polishing and rewriting and doing Draft #93 to stall the moment at which you send a piece of writing into the world for acceptance or rejection. Certainly, he didn't mean that if you write something and decide the middle is weak, you shouldn't go back and rewrite it. (As I recall, when Harlan Ellison quotes these rules, he appends to #3 something like, "…assuming you think the editorial order isn't stupid." I'm with Harlan on that.)
I'm not sure I agree with #4 or #5, which are pretty much the same rule. I have a screenplay that I wrote years ago that I liked at the time. I was alone in this opinion. No one else who read it thought much of it, not even my agent who was my agent because he liked most everything I did. At my insistence, he submitted it to a number of producers and I gave it to a few. Not only did no one leap to buy it but I came to the conclusion that it was lowering their opinions of me as a writer. That is never a good thing.
So I stopped submitting it. Years later, I gave it another read and decided I was right to give up on it. The writer who thinks he never writes anything below the standard he seeks to maintain is a chowderhead.
Once its flaws became more obvious to me, I briefly considered revising it and trying again. Then I decided that time could be put to wiser use. I have other, better ideas — at least, I hope they're better — that I haven't had time to pursue. Why devote that energy to an idea I don't even like that much now? I somehow don't think Mr. Heinlein would urge me to decide otherwise. Another maxim of the writing game is to always lead with your best. No matter what I do to it, I don't think the script no one liked will ever be my best.
As a writer, your value to those who hire or buy is that you give them something that is of use to them. You give an editor a book he thinks is worth publishing. You give a producer a script he thinks is worth producing. An editor or producer faces the same imperative as you. Just as you have to write, they have to cause product to be created. If you deliver material that make this possible, you are of use to them and they will like you (enough) and give you money (sometimes enough) and enable your work to go onto the next step of printing or publication — which is presumably what you really want.
Heinlein was railing against writers who don't write…or don't write enough. I'm with him on that. I think the profession is glutted with too many people who excuse (or worse, romanticize) non-production. Yes, you can't sell a half-finished piece. You also can't sell a rotten piece…or if you can, sometimes you shouldn't.
I don't like critiquing other writers' work but every so often, I get roped into reviewing portfolios or samples at a convention. I showed up at a con once and without telling me, they'd advertised that I would review materials by wanna-be comic book writers and artists and advise them on how much potential they had or suggest where they could get work…or something. I hate doing this kind of thing. My head is full of my own unfinished stories and I don't have room to cram someone else's in there. I also don't feel my opinions are so infallible that someone else should be basing the management of their career on them. I've seen lots of published comics or produced movies based on scripts I would have deemed unworthy.
When I'm stuck inspecting samples, one sign of outright amateurism I encounter is this. A kid will come up to show me his artwork and before I've even formulated a snap opinion — sometimes, before I've even opened the folio — they start with the excuses: "I did this a few years ago"…"Oh, I did that one when I had the flu"…"I had a lot of trouble with my pen on this one…" An oft-heard one is, "I know this looks bad there but the editor insisted I do it that way."
As I've learned from others who do these critiques more often and willingly, the proper response is to close the portfolio, hand it back to them and say, "Come back when you can show me only work you're proud of." It is usually the most valuable advice you can give these folks and I can't square that with Heinlein's #3-5.
Like I said, I'm not comfy disagreeing with one of my favorite authors but I think he would have approved of any writer who created a lot of work and saw most of it go on to be published or produced. There's also that happy bonus when you're at least reasonably proud of most of it.
Oh, and the money. The money can be nice, too.