My wife and I have used Ortlieb bar bags for 12 years and changed the map cases at about ten years (20,000 miles of touring use). They were still OK but getting a little discolored from the sun. My wife and I both replaced map cases at the same time. Our old cases were still usable so they are now on our daughters' Ortlieb bar bags.
We have the older bar bags which uses snaps to fasten the map case to the bag. It is easy to connect and take off the bag and fastens the case securely to the bag's lid.
My wife and daughters uses the Ultimate 5 series bags and I use the Classic series bag. Between us we have tested the map cases pretty rigorously
When we bought our daughters bar bags for Christmas a few years ago, we looked for the older bags that used snaps rather than magnets for closure and attachments.
