I have both cheap and expensive measuring tools. Leaving my cheap ones on the bench (where another wrench may land on it) is for a general use where getting a quick measurement comes in handy. My "good" ones are in the toolbox and in their own custom box for when I need to know I can trust the accuracy.
I do find those cheap ones basically do what they say they can though. I check them with my standards and find them quite accurate, and I'm not afraid to use them.
