Probably 20+ years ago the US Military had FDA checked out expired drugs. This is very important to the Military as although you and I can just throw away expired drugs and get a replacement down the street at our local Rx place, it is much more difficult for the Military.
To make a long story short, the vast majority solid drugs i.e. not cremes and liquids, were usable for at least 10 years. Cremes and liquids, it was found, should not be used past their expiry date. BTW, the expiry date is not the one the pharmacists puts on the pill bottle given you (I've always seen that to be 1 year after script was filled) but it is the one on the original container from the drug company.
Ps. I'm not sure that V or C were drugs the Military was concerned about.