I started using Borax when I started cloth diapering. It is a water softener, and when you have to wash cloth diapers, hard water will build up minerals in the material. Same goes for all of your other laundry! So if you have hard water at all, you should be using Borax (Or Calgon, Or Washing Soda) to mitigate the minerals in your water. Once I had it on hand, I started using it for my regular cleaning.
Even though most of the 31 points on this list are cleaning-related, there are specific concentrations and directions to follow when cleaning different things. Also, did you know Borax can unclog a drain or a toilet? My toilet clogs a lot, so I will try that next time.