No pan, whether it's nonstick or stainless, should ever be heated up without any contents inside. The cookware will quickly heat up beyond a safe temperature, (sometimes within a matter of only a few minutes) and the metal will warp, char, and become permanently damaged. This makes for an obvious fire hazard, as well as a waste of a good pan! So regardless of what cookware you go with, don't heat it up when empty. Even when you're cooking something that calls for preheating the pan, this shouldn't take longer than a minute.