ANY gasket of any type material is considered single use. However, there are MANY that can be re-used without ill effect. If you do re-use a gasket and it does what it is supposed to do, (hold oil, no exhaust leak, etc.) then you are good to go. The gamble is, a matter of how much work it will take to do over again, if the re-used gasket doesn't work. Exhaust gaskets? I re-use them all the time.