I definitely recommend using intellectual property to protect your brand. In your situation regarding your clothing brand logo, a trademark will be most helpful.
One thing to point out initially about trademarks under US law is that they exist as soon as they are used in commerce to represent your business. In other words, as soon as you sell a t-shirt with a logo on it, that logo is your trademark. Provided of course that your use of the trademark is not infringing on another’s prior use of the mark.
So, the question you are asking is should you register your trademark, because you probably already have a valid trademark simply because you have used it in commerce.
A trademark does not have to be registered to be enforced, but registration is very beneficial to enforcement. Registration of a trademark gives notice to the rest of the marketplace that the trademark is yours. It also makes your trademark much stronger in the event that a dispute arises.
At LawTrades our attorneys have experience working with trademarks and have helped many others register and enforce their trademarks. Visit ourto see how we can help you!