All aerosol products have a shelf life. Polyurethane foam products can range in shelf life from 9 months to two years. Shelf life is dependent on the valve system that is being used. We use predominately the Pageris Valve. This is the highest quality valve on the market. It is made with only plastic and metal components, thereby eliminating any storage issues. Most other foams use a rubber valve system. These rubber valves expand and contract while in storage due to temperature fluctuations which then can allow the propellant to escape the can and ruin the foam. Our plastic and metal valve does not expand or contract with weather fluctuations. For the best storage, store our cans of foam in an upright position in a dry constantly moderate temperature.