To remember the core characteristics of services, use the standard IHIP framework:
$\text{\textbf{I}ntangibility} \quad \text{\textbf{H}eterogeneity} \quad \text{\textbf{I}nseparability} \quad \text{\textbf{P}erishability}$
Because services are intangible and perishable, cost accountants must use specialized units of measurement, such as Composite Cost Units (e.g., Room-Days for hotels, Passenger-Kilometers for transport).