The four service characteristics are intangibility, inseparability, variability, and perishability. Services are intangible: they cannot be seen, tasted, felt, heard, or smelled before they are bought. Services are inseparable: they are produced and consumed at the same time and cannot be separated from their providers, whether the providers are people or machines. Services are variable: their quality may vary greatly, depending on who provides them and when, where, and how they are provided. Services are perishable: they cannot be stored for later sale or use.