Well, I successfully fixed my slipper this week, only to have it come apart again today.
The stitch work I did held nicely, but the leather seems to be completely worn out. It tore right down by the place it attaches to the sole. I can't stitch there - there just isn't enough to hold it together and the leather is weak all long there anyway.
I guess you can only repair so much. Looks like I need new slippers!
