Sometimes amazing ideas just happen as we write. Our characters say or do something we weren't expecting, and we get that happy little buzz of excitement when all kinds of minor details converge into awesomeness.
And then we realize there's absolutely no groundwork in the novel for that amazing idea.
What should we do? Stop writing, go back, and put in the groundwork for this scene to have its full impact, or keep going and worry about it during revisions?
Consider these things when deciding if it’s better to stop and revise, or keep writing:
1. Is this critical to the core plot?
If knowing how this event unfolds will affect how the story unfolds going forward, it might be worth going back and editing. Especially if this event is going to motivate the protagonist to act later. If the event is more cosmetic, or will deepen something that's already there, it might be better to simply make notes where it should go and move on. Don't risk losing that forward writing momentum.
(Here's more on the core conflicts)
2. Do you know how the characters got to here?
If the scene/moment is a great way to use what you've already written and it just needs a tweak to make it fit better, then again, it's probably better to make notes and move on. But if you're not sure how the characters reached this point, but know it happened "somewhere" between X and Y, then maybe go back and figure it out. Odds are you'll need to know that information later.
(Here's more on dealing with a character's backstory)
3. Do you even know what happened?
Perhaps you've had a fantastic idea but have no clue how it works with the book, and it's going to require some serious thinking to get it to fit in with what's already there. These are often world building epiphanies or backstory ideas that deepen the story, but they could be anything. Going back is a good idea here, because these types of ideas almost always need a lot of work and surgical editing to add them in. Too much changes in the earlier scenes to move forward without knowing how it changes.
(Here's more on researching your world)
4. Will this kill your momentum?
When you're on a roll, you're on a roll. If stopping is going to make you stare at the screen when your fingers were ready to type another three hours, keep moving. Make a few quick notes so you don't forget, then get back and let the muse work. Once done, decide if you need to go back or not.
Moments of genius can rev up your excitement about a project, so don't let the thought of "all that work" get your down. There's nothing that says you have to stop and fix it at that moment. As long as you make a note of it somewhere, you'll be good to go.
(Here's more on specific reasons for stopping to edit or moving on)
Do you stop or keep moving? What types of edits or inspiration will make you change your normal routine?