Honda uses torque to yield bolts and they should be replaced upon removal. The reason the bolts are used is to compensate for the different expansion rates for the mated metals. Once the OEM bolts have been used and removed they have been stretched...and will not perform the same the next time they are used. If you use the bolt over again, just as Blanco said, you take the chance of snapping one (bad situation). I don't know that much about ARP headbolts, but they seem to make other quality parts and I haven't seen anyone disagree with that. It's better to be safe than sorry...you can spend a little extra now on the headbolts or possibly a lot extra later if you don't replace them. I think there is also a pattern in which you need to tighten these bolts. I know on a Ford head you have to do the pattern three times at different ft/lbs in order to torque the head down evenly and completely. Sorry if the link doesn't work...it seems to work fine for me, though.