I have so many different ones, but I seem to gravitate toward the ones, that 'fit' for the size project I am working on.
I especially like my T square for corners, my 12.5 omnigrid for squaring up blocks.
But my #1 RULE lol...is: whatever ruler I start with, I keep using, bc different rulers can make you mark differently. Difference in thicknessess etc. making your marks closer or further away, even if you lay them on top of each other and make sure they 'measure' the same.
Don't mix them up...if you like accuracy! :wink: