Some people might shy away from clipart because they don't think of it, or they think it's too much work. If you find the clipart in a clipart book that will be too much work and it won't look good because you'll have to use a photocopier to resize it and then the quality degrades.
However it is important to know the different types of clip art that are available, with most clipart sites being filled with old scanned artwork that isn't very attractive. In fact a Google search for free clipart is likely to find dozens of sites filled with black and white drawings from the 1970s that was scanned and uploaded. Unfortunately this type of image isn't easy to adjust the size or manipulate.
So watch for this all month; you'll be amazed. Imagine each invite without the Christmas clipart and ask yourself, "how would this fine piece of paper look without the reindeer poking out its head, or the mini Santa graphics in the bottom corner?" Christmas clipart is a big supporter of the holiday spirit, because without it we would all be monochrome and unhappy.