Should I Trademark T-Shirt Phrases?

Dear Rich: I have a t-shirt company, and I want to know if I need to trademark each phrase or saying I want to print or do I have to list with the Supplemental Register? $325 for each saying doesn't seem to add up.
Save your money for marketing purposes. You're unlikely to get any protection at the U.S. Patent and Trademark Office (USPTO) if you try to register clever t-shirt phrases.
But if Nike can "Just Do It" why can't I? Companies can register slogans and phrases if they signify a source for goods or services. So, if M&Ms brings back their slogan, "Melts in your mouth, not in your hands" on a t-shirt, that's branding for their business. But funny short phrases that are meant to provoke thought or laughter don't serve as branding for your t-shirt business. These phrases are considered "ornamental" by the USPTO because they are a form of decoration, not a source-identifier. You will have a hard time overcoming the trademark examiner's objection ... and the $325 trademark fee is not refundable.
What about the Supplemental Register? The Supplemental Register is like a bullpen for descriptive trademarks that don't presently qualify for Principal Register now but will, after several years of use. A trademark application that's rejected for ornamentality would not qualify for the Supplemental Register. We've written more about the t-shirt business here and here.