RV Window blinds / coverings maintenance - replacement, etc

When mine broke I tied the broken ends together with a square knot. There is a lot of excess string. What I learned is you can't have these too tight. I think I wound mine around the knob too many times to keep it from vibrating down, which caused the line to break. Also sometimes the grommet that the string slides on could come out of the hole causing the line to wear and break.