I think I have run into a problem with my large 6 1/2 X 24 ruler. I'm not sure it is measuring true. Can they get wear areas and create a problem when you are cutting?

I am bad about running into mine with the cutter, so I have to replace mine now and then.
And the numbers can over time wear off.

I think that after a while they no longer lie flat on the fabric and that very slight "curve" could make a big difference. I replace mine every few years.

The corners of my rulers get nicked fast. I tend to drop them a lot. I like using a new ruler so I buy extras when I find a sale. I take my older ones to class and workshops so if they get misplaced, borrowed, or left, I don't fret about it.

I had to replace a ruler that developed a curve in the center of the cutting edge. I had obviously shaved off little bits of the acrylic in that area many times. It's probably a good idea to check favorite rules against a straight edge every once in awhile.

I have also shaved off bits of acrylic in the the corners of the ruler. Better there than my fingers! I now buy extras if it's on sale! The problem I noticed is it's not a straight even cut.

Sad to say I am infamous for cutting in to my ruler, dropping it..among other bad bad things lol
You should replace it every so often to make sure it stays true.
Hugs
April

I would replace it if in doubt.

yes the sad thing like everything else in the world nneds to be replaced.

You can check them by laying them on a flat surface. Lay it down flat on both sides, and on all of the edges :D:D:D