V-brake rubs on one side, then the other
I adjust my v-brake so that neither side rubs. The next day it starts rubbing on one side, so I adjust it so that it stops rubbing. Then the day after that it starts rubbing on the other side. So I adjust it again and then a day later it starts rubbing again on the side it rubbed on two days before. And so it goes on in an endless loop. How do I fix this?