No, you don’t have to have them. But if you do, why not make them something that will remind your guests of the unique aspects of your day. Married in the spring, in a garden? How about flower seeds or bulbs? Summer wedding at the beach? Flip Flops or take out boxes of salt water taffy. Christmas wedding? Ornaments (or personalized windshield scrapers; what can I say, I have the most creative clients on the planet….)
Another wonderful option is making a donation to your favorite charity instead of buying favors. You could underwrite any one of a number of animals from the Heifer fund (http://www.heifer.org/) and include stuffed versions of the gift in your centerpieces; you can buy bees, rabbits, goats and all sorts of creatures that are so welcome to the families that receive them. ( I bought my mom a llama for Christmas; she liked him MUCH better than the parade of slippers and gift cards…) You could donate to Habitat for Humanity (www.habitat.org) and use birdhouses or gingerbread houses for your centerpieces.
Your wedding day is not only a celebration of your joyous life with the person of your dreams, it is also an expression of your parnership in the world, your interaction with the season. Let those connections be part of this day of all days!