I vote to replace it. I actually just found some brand new (older) ones at goodwill for $1 and $2 each! I went ahead and got them. I'll have to check my ruler against our counter top. I think it's still good to go, but I have had it for a couple years so who knows. I measure by my mat b/c that's always been easier. I can't think how to measure with the ruler, especially for larger squares and things.