I think writers have an obligation both to themselves and to their readers to take seriously the editing of their work. Rabbit is quite right that it entails more than just a spelling and grammar check—although that’s vitally important as well.
Remember you said this. There are few things I find more infuriating than an author who is too lazy to edit his work. I realize that it is difficult to catch everything. You know what you meant, after all. Still, laziness is not the same as mistakes and it is obvious when an author is lazy.

It is hard to go back and take whole sections out that don’t serve any purpose but the story will be better for having them gone. I sometimes have to wait a week or longer before I can go back to edit my work. I find it difficult to be ruthless enough while I’m still in love with the plot or the characters.
A week between editing is a wise choice. Also, it is good to break your story into pieces. It is also a good practice to read and edit what you have already written before going on to the next part. It helps you stay acquainted with your characters and plot line and better enables story continuity. I once had a girl cuffed in one scene and then free and moving about a chapter down. She was never uncuffed. Thank goodness for meticulous editing on my part. It still wasn't a great story but it didn't suffer from lack of continuity. I am sure you know, continuity troubles can be a bullet in the heart of a good story.