If you wear belts, you might decide you don't need to repair the button because the belt hides it, and duplicates its function of holding the pants up. This wil

If you wear belts, you might decide you don't need to repair the button because the belt hides it, and duplicates its function of holding the pants up. This will eventually result in the zipper breaking, which cannot be hidden with a belt, and is much more difficult to repair. The button has the additional non-obvious function of reducing load on the zipper, so you should repair it even if it looks unnecessary.