Here's a fantastic idea.

Since the word "anniversary" actually means "the annually recurring date of a past event," that is, it already contains a form of the word "year," in Latin, you could save a lot of words when you're talking about the anniversary of something. Get it? Anniversary means year!

So, instead of saying "it's the five-year anniversary..." you could say, for example, "it's the fifth anniversary...." This will work with any number. You know, like, "It's our thirty-fifth anniversary," instead of "our thirty-five-year anniversary." Slick, huh?

Feel free to pass this idea along to others. You don't have to credit me. I don't mind.