Engine speed: The engine-speed numbers that most vendors quote are supposed to be indicators of how fast a big print job will take, but printer makers usually calculate them using methods that do not reflect real-world usage. For instance, the printer may be in its faster "draft" mode for speed tests, even though most people print in default mode. Or vendors might omit the first-page-out time (how long the first page takes to exit the printer) from their engine-speed calculations, because it includes an image-processing delay. Unfortunately, that delay is an unavoidable part of any print job that a regular person does.

An example of a more realistic engine-speed indication is the ISO/IEC 24734 "Laser Quality Print Speed" standard, which prints in default mode and includes first-page-out time. Related:

Monthly duty cycle: This number is an indication of how durable a printer is, so it's an important metric for businesses or other heavy-duty use cases. Some lower-volume printers, such as the one you probably use at home, will not even have a duty-cycle number.