You have to pay bar dues for your state, meet CLE requirements, and so on, or you can be administratively suspended by your state. If you are, you can’t practice trademark law before the USPTO. There was another recent OED decision recognizing that basic point, here.
The USPTO once considered making practitioners take CLE, but that failed. But, you can be administratively suspended by the USPTO for various reasons, including failing to keep your contact, and other, information current under 37 CFR 11.11. The USPTO periodically sends surveys to practitioners and those who don’t respond get their names published, and if they fail to correct the problem, they get administratively suspended from patent practice, as shown here.
Either circumstance can create lots of problems for practitioners. You may need to alert the USPTO of state administrative suspension, or you may need to alert your state of USPTO administrative suspension, and so administrative suspension can snowball into a reporting problem. Further, complicated questions are created for your clients, such as (a) trust fund issues; (b) privilege issues; (c) perhaps unauthorized practice of law problems (e.g., a corporation has to be represented by a lawyer); and (d) substantive issues, such as whether something filed with the USPTO by an administratively suspended practitioner can be held ineffective or otherwise cause invalidity or unenforceability problems. And, of course, communicating administrative suspension to a client once it is known is another one.
So, pay those bar dues, go to your CLE, and keep your contact info updated.