Many factors can affect the life of a photographic print.
Improper processing Light Heat Humidity Atmospheric and environmental contamination Fungus and bacterial growth Surface contamination Abrasion Photographic prints can have a long, useful life when they're properly processed, displayed, and stored. If you process your own prints, closely follow the manufacturer's processing recommendations. Use fresh fixer, and be sure not to use the fixing bath beyond the recommended capacity. Wash your prints for the recommended time. Residual silver salts and traces of fixer in the paper may cause stains, uneven tones, and fading.