The size of the paper input tray is important. If you can load 200 sheets of paper into the printer, it not only means you have to change the paper less often, it also means you can set the machine to print multiple copies while you get on with something else. Printers that take only 10 or 20 sheets need constant attention.
Incidentally, check the size of the output tray as well. Some printers have output trays that can't accommodate the entire contents of their input trays.
Some printers come with an extra input tray that can be used with envelopes or a different size of paper at the same time as the main input tray. Others use just one multi-purpose input tray, in which case, if you need to use several papers, you'll be constantly changing the contents of the tray.
