From Brandon Sandersons lectures in 2014. The first lesson is about the different types of authors. The Gardener and the Architect.
This type of author wants to write the book from front to back with little help of notes. The result is often very good a realistic characters. They are written as the do what they do. Everything fits into what the character should do and nothing is forced. But the problem is that the endings are not as good and well built. You usually have 6-7 times the drafts that the Architect have.
This type on the other hand are the reverse of the Gardener. The stories are well-built. The drafts are often not in the double digits. But the characters can often feel forced. A character can some times do things that may not feel like their personality. But they have to do it to fit the story.
Which to choose?
Most authors falls in between these to archetypes. Garderners use a few milestones. Architects use many milestones but characters are written more fluidly. Most authors lean towards the Architect type as the writing becomes easier. But there are many gardeners out there to. One is mentioned in the lecture.