An expendable supply includes a memory that stores a timing of a last warning after a recommended limit. A warning generator of a printer determines whether to generate a warning upon occurrence of certain operations. The warning generator generates a warning when the last warning generation time is not stored in the memory of the expendable supply upon detection by a printer detector, or upon the last warning generation included in a first time period is stored in the expendable supply memory at the detection by the detector and the first time period has elapsed at the detection by the detector. A warning is not generated upon the timing of the last warning generation included in the first time period is already stored in the expendable supply memory upon detection by the detector and the first time period having not elapsed at the detection by the detector.