I think it is significant enough to replace. I had a 6" square ruler that was worn down on one corner because of my rotary cutter getting too close and shaving off just a sliver every time I used it. This will not give you a straight cut.

My very first quilting supplies purchase was a package that came with a small cutting mat, rotary cutter and 6 x 18 inch ruler. Along with a quilting 101 type book. Nothing ever came out accurate, everything was too short, but I kept fussing along. One day I used my husbands carpenter's ruler, the metal roll up kind, and measured that ruler. Come to find out, the 1/4 inch mark was not a full 1/4 inch. It's a wonder I hadn't given up on quilting before I found that out. Needless to say, I bought a better ruler!

Periodically I put my rulers on edge to see if are warped or curved and I store them nicely and flat. I drop stuff a lot, partly because of my lack of depth perception I think. But my iron gets dropped, my coffee cups get dropped and my rulers get dropped and shatter often enough to be replaced.

We each have a slightly different hand to our cutting whether we are completely perpendicular to the ruler or slope in or out. I prefer to use all of one brand of rulers on each project if I can, I think some are better used on the line and some are next to the line.

Out of caution I replace my ruler every 6 months. A 1mm difference can really set off my block.

Mine may be but not where it makes a difference. I just keep using them.

I agree! I don't donate my used rotary blades so why would I donate used ruined rulers?

This discussion leads me to wonder... are our old rulers recyclable?

I'd better check my rulers today. I do have a new favorite, though, Creative Grids 2 1/2X 24". My others are omnigrids and they are going to get checked today, one is 3"X18" and one 3 1/2X24. I think they have probably earned their way to the trash bin.

Never thought of this and I have been using the same rulers for o/12 yrs...Guess it's not making any diff so no replacements here..