Staple binding is how most calendars are printed. These calendars are printed as a stapled booklet (saddle-stitched) where pages must be in multiples of 4. This type of calendar requires a minimum of 28 pages.
Unlike stapled calendars, spiral bound calendars can be printed with any amount of pages. This allows more flexibility for your number of months, notes pages, featured products/services or other content.
Wire-O bound calendars are very similar to spiral calendars but are assembled with a metal wire instead of a plastic coil. They tend to lay more flat and have better registration across the gutter / binding area.
A bleed is where printing goes all the way to the edge of the page. This is also sometimes called borderless printing.
With non-bleed printing 1/4" white margin will be added along the edge of the page.