I usually will incubate 'ideas' for years as my stories takes several years to complete.
For example, I wrote the rough draft of my first novel in 2004. Completed 2007. Selfpublished 2010. Wrote the second part in 2010, edited in 2011, and self published in 2012. I wrote the outline for the third in 2012 and began writing but it remains unfinished.
This was a three part book series called REVELATIONS. The first two books available on AMAZON,
I began outlining THE SOUL COLLECTORS, my current series in 2016. It is complete and I am just releasing it on TAPAS now, doing extra art for the series as I go.
My WRITING PROCESS, after I've let the idea incubate, is writing the parts of the story that ran the most in my head. The scenes I build in my imagination. It might be a scene in Chapter 2 or 20. The final scene or the middle romance. Whatever.
Then I will connect it all together.