Duplicate event listeners

1

some time ago i asked about this, and i believe it was senocular who advised me nothing happens if you attempt to add an already existent event listener.

example: this only fires once per frame


addEventListener(Event.ENTER_FRAME, myFunc);
addEventListener(Event.ENTER_FRAME, myFunc);

So im wondering now, as coding practice does anyone ever run a function, or a class, to like clean all possible event listeners in the class upon destruction? Whether they exist or not.

function cleanListeners(){
  //  remove mouse listeners
  //  remove enter frame listener 
  //  remove ...well i suppose i don't really have that many listeners
}

So even if the listener is not there, the only down side i see is possibly running a few extra lines of code and the speed associated with that.