Charlie Ryant, a terrific senior creative director, used to have that sign over his desk. It always made us laugh – but the truth is, “sometimes yes, sometimes no.” Sometimes you’ve got to go with your gut and sometimes you’ve got to get some feedback before you risk it all. Be very careful about what you decide to test and what you don’t. In fact, you may want to “pre-test” the testing. Gather an informal group and run the idea by them; if there’s not unanimous response, it’s a good signal that some serious testing might be in order.