I am a very linear writer, I can only think of a handful of times that I deliberately wrote a scene out of order (as opposed to relocating a scene after it was written). I might have the end of the story in my head, but I don't write it until I actually GET to the end.

I'm pretty good about completing stories. Yeah - there are some incomplete series in my backlist but I always plan to finish them (hence the New Rule - no more posting Works in Progress), My WIP folder is surprisingly small - maybe a half-dozen actual stories (as opposed to notes). The oldest dates back about six years and I really do intend to finish it. More complex stories tend to get pushed to the side for a while - historic A/Us, emotionally complex tales. But I do go back to them. Nothing's ever really abandoned.