I've been checking websites for printers for sale, and sometimes it states that a printer has a "monthly duty cycle" of a certain number. Sometimes 3000
Would anyone know what this "monthly duty cycle" relates to, and what is a good number to have?
It is the number of pages which you can expect to get out of the device without problems, but it is only a relative guideline.
In other words if you maybe print 20 pages a day and work 20 days a month (4,000 pages a month) you could probably get away with something with a duty cycle of 3,000, but you might find it wears out earlier than expected. Something with a duty cycle of 10,000 would be more able to handle your throughput but will cost you more.
In the bad old days some fax (in particular) manufacturers used to build in obsolesence into their toners where the device would report that the toner was empty (and refuse point blank to print anything) when it patently wasn't empty, but I don't think anyone does that anymore.
Some other devices may give a cycle per element (fuser good for 50,000 pages for example), but if it is given as a monthly figure then I would take it that it is a recommendation.