once spring rolls around ill be replacing my front rotors (along with pads) and i know theres a retaing nut/clip type thing that holds the rotor inplace and im wondering if its possible to remove this with out destroying it and if not is it absolutley essential to put a new retaining nut on after the new rotor?

 

Toss it. It is there to hold the rotor in place on the assembly line while the other parts are put on.