He said it already. Torque To Yield. Once the bolt has been torqued to spec, it cannot be reused.

However: I re-used mine when I built my D15B7. Haven't had the first problem with leaks or anything. I torqued them 1'lb higher than spec. Don't try this at home, I'm just a cheapa$$ ba$tard. Make sure you oil the hell out of them before torqueing or you could snap them without even reaching the torque spec.

OEM bolts stretch. Most ARP's can be re-used because they don't.