Monthly Duty Cycle / Maintenance Interval

[rll]

On the list of refurbished printers, the monthly duty cycle of LaserJet
4V and 4MV is shown as 50,000 pages; whereas on the HP web page below
it is 35,000 pages.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=bpl04585

Which is correct?

The maintenance interval (e.g., 200,000 pages) is how long you can
expect the fuser to last before you have to replace it?
Where are the maintenance interval ratings obtained from,
and why are some printers such as LaserJet 2100 unrated?

Or is the fuser lifetime more like "200,000 pages or X years whichever comes first"?

[MichaelTech]

You have to realize that these are really HP's guestimates based on their testing under their conditions. And you know the next thing Im going to say...
Your mileage may differ! Depending on paper type, type of document formatting, usage, it rarely gets to the actual "expected" use. Plus, any number of things can be a factor in how long products last. Genuine HP? or third party refurbished? Save a few bucks here, spend a few more there, it's your call.
On units like the 2100, 2200, 4000, they have several integral parts that wear out about the same time, and if nor replaced together, will cause problems again and again. If you refurbish these units, get used to replacing at least three parts:P\U roller, Feed Assy., and the registration.
"Impatience will reward you with dissatisfaction" RMSCosmics 1984