Writing/editing

How long it takes to edit your book.
I must have re-edited those first six/eight chapters a dozen times. I only hope each time is improving them, not annihilating them.
The balance of each sentence, not repeating your story, improving the thrust of the story line. On and on. Hours, weeks and months of work. How can you speed this up...?
Arrrggg
And, should you....?