Typically, if the bolts are non-structural, then reuse them all you want.
If the bolts are structural, and they have yet to be loaded or fully torqued, then reuse them. If the bolts have seen service loads, or have been torqued to their higher end, toss'em to be safe. Finally, if there are locking features on either the nut or bolt, toss the respective part unless there is specific data to support reuse.
At the company I work for, aircraft OEM, bolts needing to be reinstalled at the factory are not typically tossed as they are 1) very expensive, 2) torqued to values below yield, and 3) some have specific retorquing procedures based on the inherent locking features. However, bolts replace in the field are strongly recommended to be replaced, no matter what condition they appear to be in.
jetmaker