If you are going to bind the calendars yourself make sure you select the equipment suitable for the task.
I already have a plastic comb binder but thought calendars would look better using wire so I ordered one.When it arrived it was tiny, plastic, and only had the capacity to punch 8 x 70gms sheets of paper at a time. What. I was using 170gms paper and 100 calendars would be 1400 sheets (front and back plus 12 sheets) You do the maths and decide how long that would take. So back I went, read the specifications in full and bought a heavy weight model. This one weighs so much I can just move it around but it easily punches the whole calendar excluding the back at one go.
Quality check the first sheet when you change months.
I left the printer happily printing 100 sheets to find when I returned that I'd used a different font for March so they all need reprinting.
But I have now assembled my first calendar and despite all the set backs along the way I'm really pleased with the end result.