I have the Creative Grids in every size from 2.5" to 12.5" square. Some are quite old and well used; I recently noticed that a corner of one is starting to wear away a bit.
Creative Grids does make a tape that you can apply to any brand/size ruler. It's not inexpensive, but works great. I know some also like to use Nexcare Flexible Adhesive Tape (sold in first aid department w/ bandages). Have not tried it personally.