Tampons can expire, but the length of time before a tampon expires depends on a number of factors, such as moisture, contamination and temperature. Perfumed tampons expire more quickly than nonperfumed tampons.
In a cool, clean, dry environment, tampons can last for years without losing their usefulness. However, tampons are not sterile, and the presence of bacteria can break down the tampon's materials, causing decreased absorbency and possible vaginal irritation.
In damp or dirty environments, tampons can become contaminated with dirt, dust or mold. Never use a tampon that appears dirty or moldy, no matter how old or new it is.