@lewiscowles1986 I have no idea what the "header file" has to do with it.
For PHP, hook inheritance is basically the same as methods. You override the parent hook/method. You can call it if you want, in which case it's the cost of a method call, like overriding any other method.
If your inheritance hierarchy is deep enough that it causes a performance issue, then your hierarchy is too deep and that's the issue to fix.