As someone who's shied away from outlining in the past, I'm starting to see how useful it is. But even at that, I don't always outline: it depends on the story. Some stories come easily and don't require much prep. I'm 90 pages into a romcom that required hardly any outlining, bar a brief run-down of the plot. Another idea is still in the very early stages of plotting as it's incredibly complex and detailed. This will require a very extensive and comprehensive outline if I'm to make it to the first draft. I'm also outlining another thriller in great detail and it's proving an enlightening experience. I'm finding nuance and unique details emerging now rather than the 15th draft, thus saving me time.

I take it you mean with outlining something as a beatsheet or treatment? I'm not that seasoned that I could do without some plan.

Hell yes, outline! I'm a very prose-heavy outliner. It helps me organize thoughts and map out the different stories and paths within the main plot.

I do the 9 beats so I know where I'm headed - then I write the first draft - and then I outline...from there it's all about heavy revising/editing and that includes the outline as I revise the spec.

As noted frequently, there is no right way to write. However whenever I meet an novice or intermediate level screenwriter who has NOT ever worked up an outline, I encourage them to try it at least once. The simple fact is, you are going to have to wrangle your story at some point. Why not do most of the grunt work BEFORE you type FADE IN? You are much less likely to get lost in the page-writing process, lose faith and quit. Moreover when you do start writing pages, you can focus more on the nuances of each scene rather than dwell on, "Does this work per the plot or not."

If a person is going to get frustrated and quit when they run into some grunt work, it doesn't matter if you grunt before you write, in the middle of writing, or when the project is done. Grunting just isn't you're thing and it's time to get in line for a job at WalMart. There's no way to get around the grunt work, so pony up. I've worked with and without outlines, and those stories I do without an outline have worked much better than starting with an outline. That's me and I wouldn't suggest anybody else change their ways because of how I create. Golly-gee-whiz, can it be called Creating if there's only one way to do it? I know men don't even want to try relating to the ultimate act of creation -- birthin' a baby -- but there are a whole bunch of parallels, and not just the grunting. There's a part of the "process" where the mother-to-be, with full sanity and a grasp on reality says, "I've changed my mind. I don't want to do this. Let's go home," and we MEAN it. It makes exquisite sense, and it takes a whole bunch of talking to convince us it's not an option. Same holds true with a story that's taken shape in a part of our thinking that cannot be denied. I call it a fertilized story. We will want to quit, we will think we can quit, we will start heading for the door, but it ain't gonna happen. That story must be told, and we do whatever we've got to do to get that damned thing out. Quitting is an intense part of the creative process we need to acknowledge a whole bunch more and start learning to deal with. Pressman does a beautiful job of this in his book The War Of Art. The more absolute that story inside of you is, the more you will resist it. Get over it, do the work, act like a pro, and grunt when you have to. If you need an outline to get through the sweat and the fear and the hard word, outline. If you need to free write getting over that hump, do it. If you're a messy person and enjoy getting in a mess with your script, do it. There's no way of getting around the rough spots. So grunt loud and proud.

I'm glad CydM commented because I couldn't remember where I'd seen this comment re: writing the first draft, then the outline. Sounded so far-fetched to me at the time... and then it happened. I stumbled upon an idea that just had to get down as pages first! It was the first time I didn't have to delve into any research so I just went for the pages to see where it flowed... and then circle back to the outline. Now I 'get' that process :)