Ideas and book writing

I have a file where I write down new book ideas. I open it up every once in a while and read it, sometimes add to it. I've decided that since I seem to be getting to a point in my werewolf book that I'm bored with it, maybe its time to start a new book. Maybe put the werewolves on the back burner for now, and start a new one.

I started a new file and chose one of my ideas. The first page lists my idea and I just got done typing up something about the main characters. Mainly, describing them and their part in the book. Now, I've written 4 complete books and my 5th one (the werewolf book) is still in progress. For two of those books, I listed out the characters, their details and background. This new one I've done that again. so half my books started without much of anything except the idea itself and the other half started with details of the characters. I don't know which is the better way to do it.

Now, just because I've written the character info down ahead of time, doesn't mean it'll stick. I'll probably change the details as the book progresses depending on how the characters make themselves known. I don't write every detail down, I don't make an outline of the book. I have a general idea of what I want to do with the book, and sometimes, my idea, my characters take things in to their own hands so to speak.

Knowing this, I can't help but wonder what the purpose is for me to even write down any details ahead of time. It's odd.

I just thought I'd post some random book thoughts since I haven't posted in a while. I'll try to post more for any readers I might still have