The problem with replacing zippers in leather is the old needle holes don't close up like cloth does. If the zipper is sewn so the stitching is visible, the new zipper has to be sewn in exactly the same line or it will look terrible. It takes a very steady hand to do it right.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.