The reason Volvo requires new bolts to be fitted in critical areas is due to the fact that angle tightening is normally mandated. This method of torque loading takes the fastener beyond the material's elastic range. If this is done more than once, then it can have serious consequences on the material. The reason that angle tightening is used is that it is a very accurate method of torque loading.

On most new GM vehicles, in order to reinstall the caliper bracket, you have to have a torque angle gauge and two new caliper bracket bolts. The bolts are Torque-to-Yield (TTY) fasteners that stretch. TTY fasteners are mounting fasteners which are torqued beyond the state of elasticity and therefore undergo plastic transformation, causing them to become permanently elongated.

From a Ford GT development engineer: in a non-fatigue environment (e.g. one in which the bolt sees constant, non-varying load which the connection designer wants to strive for and can design for), the bolt is just fine being loaded into the material yield portion of the stress-strain diagram. Typical "critical" bolted connections (ones where particular attention to detail is warranted) use high strength fasteners (good, controlled, and specified material properties) which have good elongation properties which enables loads into the yield portion of the stress/strain curve.

The bolt will work just fine even after being loaded above the yield strength (stress) of the material. Good bolted joint engineering design practice is to torque a bolt to 90% of material “proof strength” which is roughly equivalent to 90% of material yield strength (refer to Shigley's Mechanical Engineering Design).

Thread and head collar friction loads (which consume a large part of this initial torque before the torque can result in clamping load) are very large variables in bolt torque calculations. If the installer puts the nut on dry, with factory-installed anti-seize during assembly, very large swings in the amount of actual load that the initial torque produces in the fastener can and usually does occur. Thread lubricants (including pre-coated bolts) can significantly alter the thread friction which consumes torque before producing bolt clamp load. Thus, in reality, a properly designed bolted assembly using anti-seize (when torquing guidance does not specifically call out use of bolt lubrication) torqued to specification can load a regular bolt into the material yield range easily, without the assembler knowing this fact. To be safe, one should follow the replacement instructions dictated by the OE, but it would be interesting to have the application designer state, why. If reusing, I would just watch for damage to the bolt coatings and replace them if the coating appears compromised because it may seize in the aluminum if it is left in there for a few years.