Wasn't going to talk about hardware or whether to replace any or not, but thought I would share some insight. My neighbor is a senior assembly engineer for the BMW factory nearby and told me this in reference to hardware, torque, assembly etc. Kinda long winded and I apologize for that, but if you are "detail-oriented" (read:anal) like me, it's fairly intriguing.
First, most of the hardware used to put our cars together is not very sophisticated like true "yielding" hardware is. Torque yielding hardware is very specialized and made of precise metallurgical alloys. Most are "waisted" meaning that there is a section that is thinner and non-threaded that will give way when over-torqued, or over stressed, to prevent damaging the assembly components. The metals used are very consistent with their fail rates and tolerances. They are also hideously expensive. The hardware use to assemble our suspension pieces is not per se. There are pieces that are hardened and carry a higher grade, but most are cold-rolled steel.
Second, we have to look at what a fastener does in these applications. When tightened, they stretch and produce tension which keeps assembled stuff together and the bolts/nuts from loosening. There are also fasteners with limited use/re-use that include eccentric locking nuts (they look slightly squished) and nylon inserts to provide a high degree of friction to prevent loosening, especially due to vibration. Both of these will lose some of this friction each time they are disassembled. There are others, but trying to focus on what we have to deal with regarding the suspension. Bolts will also lose their ability to provide a prescribed amount of stretch, and thus tension, depending on how many cycles of assembly/disassembly they are put through.
Lastly, when the factory prescribes a specific torque or tightening sequence/regime. It is because there are variables that need to be overcome to produce the proper amount of stretch. According my engineer neighbor, in the applications where we have to make additional degrees of rotation to a fastener, it is mainly to overcome some inherent elasticity in the pieces we are fastening (such as the strut pinch point, control arm to damper interface etc.). The torque figure will "take up the slack" if you will, while the additional rotation ensures that the extra elasticity is defeated. One area he mentioned is the channel of the rear control arm where the end of the damper locates. The control arm is made of steel (in most cases) and has some "spring" in it that can "unspring" when flexed. This can relieve tension and allow the fasteners to loosen. Overcoming this natural elasticity with additional turns of a fastener helps keep this from happening.
So, WTF does all this mean here? Well, if you prescribe to the follow the letter of the law approach to hardware, you will be inclined to replace all that is unfastened as outlined in the factory manual as the factory is bound by liability reasons and such. If not, you will trust that unfastening and fastening hardware will not make it un-usable and keep on putting things together with what ya got,. If you're somewhere in the middle, you understand that hardware will lose it's ability to stretch properly and fail at some point depending on how many cycles of use it's put through. The choice is your's whether to re-use or replace, this is again to give some insight into fasteners from the perspective of someone who does this for a living.