Registrations require renewal. Trademark law prevents consumer confusion as to the source of products or services. There is a second minor trend that trademarks are like property and diminishment of value is basis for an infringement action. Common law trademarks, i.e., unregistered, exist in the area in which the mark is being used or is known. State registrations exist throughout the state.
Federal registrations exist throughout the country.
First in time is first in right. Thus, two or more users may all have the same rights in different locations if the first user did not promptly obtain a federal registration. Federal registration is a must to avoid future expansion problems due to geographic scope issues.