1) Military discharge and commendations: The DD214 is the most important of these documents for obtaining job preference, VA medical benefits, and ultimately, death benefits. Commendations should be kept in case someone ever questions your military service record. Saving those records will save countless hours and dollars trying to get copies from the military.
2) College degrees, records, and national test results: If your alma mater's computers ate your records, your copies will help restore the data. These records are useful when filling out late night job applications. Keepsealed envelopes of your GMAT scores, for example, if you wish to pursue a master's degree.
3) Birth certificate, social security card, passport, and old military ID cards: These should be kept in a fireproof safe. Although copies of these documents can bo obtained, most are used so frequently that it just makes sense to keep them nearby.
4) Insurance papers: All current insurance policies need to be kept, as do agreements for underage car accident victims. Often when a child turns eighteen, insurance companies need to have the young adult sign off on any previous accident claims. It is wise to have the original agreement.