Oh, good question.
I suppose it depends if you plot / outline or not and what you mean by the "end".
I do outline / plot, so in some sense I've already written at least part of the big final confrontation and I know where I want to get to with my characters by the end of the story. I tend to write in order for the most part, and make handwritten notes as I go of things to pick up / remember as I get towards the end of the book.
However, I also find there needs to be at least one or two scenes after the final confrontation, so the big final battle, for example, isn't actually the end. I don't always sketch those final scenes out until I'm almost there, or sometimes just when I get there as they tend to pull together things from earlier in the book.
I do skip ahead sometimes to scenes I really, really want to write - quite often when I'm writing those, something else fires in my brain and gives me some breadcrumbs to seed into previous scenes.
The mysteries of writer brain, eh?!