Digitize them soon. My family has photos from my grandparents' childhoods, and firstly, no one can remember who the people are, and secondly, they are fading to the point that they appear gray on gray. Contrast stretching can almost fix the graying of the old photos, but the old relatives who could have recognized the people in them (or even the locations) have and are dying before we can get them annotated. Likewise, we have the same problems with pencil writing (yes, even on important documents).
On the other hand, we can make fun of my one great-grandfather, who wrote to his future wife for several years, but used the wrong name (that should teach parents NOT to name their children with obscure four syllable names similar to other ones) until about 18 months before their wedding, which was probably the urban equivalent to a shotgun wedding.