Information was requested as to the shelf life of electrolytic capacitors. The shelf life depends on storage conditions. Temperature, atmospheric pressure and humidity. Electrolytic capacitors are most susceptible to high temperatures. The current aluminum electrolytic capacitors shelf life is approximately 2 years. If storing these capacitors at a high temperature rating, it can degrade the sealing material. When the material is degraded it can cause the electrolyte to dissipate and change the characteristics of the capacitor values. Mainly a change in the leakage current. Moisture can also be a factor in causing the wire leads or terminals to oxidize. It is also important to note that other factors that should be avoided when stored. Radiation, oil, ultraviolet rays, and ozone. When storing electrolytic capacitors, it would be a good practice to log when the storage of these devices has started.
Here is another post with some general shelf life information.