as with all mechanical devices relays have design limitations and must be selected accordingly. the loads dynamic characteristics determine the quality and hence price range required ie if the load is an ac line operated motor the inrush current can be 10 times running current ,with this high current condition occuring while the relay contact is bouncing thus oversized silver (expensive) contacts and arc chutes may be needed. The load may be very inductive such as a an arc welder with a high frequency signal superposed for tig welding. In this case the relay may be used to apply the hf signal ( low power) yet be affected by the high power disruption occuring at make or break. What I am saying is that each case needs to be evaluated by the applied load characteristics not "blanket" solutions