Of course it's just good hospitality to leave Santa (and those reindeer) a little something on Christmas Eve when they visit your home. They're working hard, and they need the energy...
When we were growing up, we left the traditional cookies and milk, plus a few carrots for the reindeer. There were usually a few crumbs left, and there was always a note from Santa in very shaky handwriting thanking us.
There's so much opportunity here to add a little magic. We did a little hunting around online and it seems some people sprinkle glitter on the lawn where the reindeer landed. (I guess this is if you don't have a chimney).
Here's a list of other ideas for leaving Santa Clues if you feel inspired.
Image: Paige's Pastime Etsy Shop available for purchase!