There is no way to determine the actual number of pages that have been
printed on a Personal LaserWriter LS and Personal LaserWriter SC controller
board or print engine. The Personal LaserWriter NT controller board stores
the number of pages that the controller board has printed, but not the
number of pages the engine has printed.
With the Personal LaserWriter NT, the customer can keep track of the page
count using the controller board (user test print). If the controller
board is never changed, the page count should be accurate. If the board is
repaired or replaced, the page count will change, and it is the customer's
responsibility to monitor the printer's page count. Since the Personal
LaserWriter LS and Personal LaserWriter SC do not have the controller count
capability, the customer needs to keep track of the page count. To assist
customers with this task, Apple offers the Repair Log Label (part number
826-0481).