New fasteners or replace?

Hello! I have a 27-year-old metal roof. I think it's a galvalume R panel, white in color...although there is a lot less white and more of the base metal color showing in places. Just last week we got some heavy rain that lasted for a couple of days and I noticed a leak. The leak location is in a flat section and almost has to be from a failed fastener. So, the question is, pay almost 20% of the cost of a new roof for new fasteners, or just bite the bullet and go for a new roof. I got a quote for a new standing seam metal. Thoughts and advice are greatly appreciated.