Re: SRB Reuse
Yes, they are reused; no, I don't have any figures on reflights. The forward skirt and frustum, aft skirt, ET attach ring, parachutes and wire harnesses are refurbished at KSC (I currently work a couple hundred feet from the hangar where the SRBs are stripped down for refurb). The motor segments are sent back to Utah for cleaning and reloading by Thiokol.
The contract awarded to Thiokol covers the expense of the rocket propellant and the labor and shipping costs required to turn around the segments for flight.
-Kim-