We use cloth napkins at our house because it reduces waste and I don't have to keep buying them. Some of them are starting to get a little worn as you saw from the last FO post and I've been putting off repairing them, but since they're just squares, the repairs are pretty straightforward.
The one on the top had been frayed on the edges, so I trimmed it up and added a new hem.The one on the bottom is what it originally looked like. The repaired napkin is a little smaller than the original, but that's no big deal.
Here's a closeup of the new hem on top of the old hem and not a bad little job of mitering the corner, if I do say so myself.