Who to buy a set of heads from??

I mean if you get the Edelbrock heads and you pop a spring off and you can't Hammer the valve out of the valve guide it's pretty much time to just send it back? Or if it drops out and rattles around in there it's time to send it back? Or if you poured carb cleaner inside of them and it leaks out time to send them back? Or if you put a flashlight behind valve in the dark and you can see light coming out around the valve it's time to send them back?