Depends on the crossbow. I have an Excalibur which is a recurve so I take off the dissipater pads and unstring it when I am not going to shoot it for awhile so the limbs have a chance to relax. My dad has a Parker Terminator which is a compound crossbow. he does nothing to it he just puts it away. It is important to store a strung crossbow in a cool dry place. Leaving them in a hot car for instance can damage the limbs.

I am not aware of any crossbows that would require you to "loosen the limb bolts" and with the poundages that are involved in a crossbow I think that doing that would be ill-advised and could get very exciting (in a very bad way) if you hit the end of the thread on the limb bolt. As always the best thing you can do is read the owners manual and follow the manufactures instructions.

Bob