It’s common for horse owners to use rubber bands to secure mane braids. The reason we avoid doing this is because over time rubber bands cut and damage hair.
Small rubber bands that are put in tight to hold braids in place create tightness and pulling on the mane, which leads to the bands cutting through hair. This happens especially when rubber bands are used and are left in for too long.
The difference between a dream mane and a mane in progress are the little things. Make sure the tools you use aren't damaging or cutting the hair you are working so hard to grow.