One of my cousin's daughters has taken on the mantle of family archivist. While at a family reunion a few years ago she brought a quilt to show me that was made by my grandmother with the hope I could repair it. I am estimating that it was made in the 1920's from dresses and shirts that had seen better days and were recycled into a quilt. Maybe some feed sacking too. It had been patched/repaired by my grandmother with odd bits of kitchen toweling that looked to be from the 1950's. Most of the fabric was seriously faded, thin, full of weak spots and had many spots where the batting had broken through. I would call it fragile. My recommendation was to cherish it but to leave it as it is. The piece is precious because it is part of family history, but sadly there was or is so little solid fabric. A repair would mean the destruction of what was the work of a college educated, depression era, farm woman who made due with what was at hand. But take it and repair it? I would not even consider deconstructing it or even patching it. Any changes would be glaringly obvious. I count it a privilege to have held it in my hands and to gently explain to this dear young woman why her yearning to restore the quilt was not wise or possible.
When asked about repairing a quilt, I will only do so if the repair will extend the life of the quilt whether it be for longer use or to preserve the beauty of the quilt for posterity.