This was one of the questions that didn't get answered during last week's CFC webcast, "Determining Your Client's Budget Before You Start." (You can still hear it here: http://www.mydesignshop.com/product/determining-your-clients-budget).
The complete question was: Should you set up a "client reward" discount for good clients as a thank you for business… toward another project with you?
I'm not a big fan of discounts because I think it diminishes the perception of your services in the eyes of your clients. However, there are certainly things you can do to thank your clients for their business.
How 'bout throwing in something extra on their next job? It is a variation on a discount but makes it "additive" rather than "subtractive" (is that a word?).
If geographically possible, I suggest you treat them to a nice lunch or dinner as a way to show your appreciation. This has the added benefit of face-time, which can only strengthen your relationship.
I'd love to hear other suggestions so post your comments. And if you are offering your clients this type of discount, how is it working?