Being a historian can be expensive. In addition to all the costs we shoulder (research trips, journals, books, reproduction fees, computers, software, etc.), we must decide whether to spend money on memberships to professional historical associations. If you can swing it, I believe you should join at least two professional historical associations: the American Historical Association (AHA) and the primary organization for your specific historical field.
Why join the AHA?
The American Historical Association is the organization for our guild, even if you work outside of academia. The organization advocates for government funding for archives and historical research, and it keeps tabs on legislation that has the potential to either benefit or hinder our work. Basically, they focus on and monitor potentially important issues so we can concentrate on our historical pursuits.
The AHA also facilitates the largest discussion forum for issues relating to the profession. Non-Academic historians should particularly care about this work as one of the organization's main conversations is about how to dissolve the gap between academic and non-academic historians.
Aside from this advocacy work, I find that the AHA has 3 practical benefits that makes membership worth the cost:
1. Subscription to Perspectives on History: AHA's publication about the guild, Perspectives provides short, concise articles about technology and software that can improve our productivity, how other historians work and teach, happenings we should be aware of, and updates on the organization's advocacy work.
2. Fellowship and Prize Board: Historians need fellowships and the AHA makes it easy to search for them on their website and, as the association for the guild, most prize-granting organizations advertise through them.
3. Reduced Admission to the Annual Conference: The annual conference focuses on the profession not a specialty. The conference features many networking opportunities, panels where historians from different fields make connections across time and place, and a plethora of panels that discuss methods to improve the way we work or techniques we can use to market ourselves to potential employers. Read Kenneth Pomeranz's Perspectives article for more on why the AHA offers a great conference.
Why Join an Organization for Your Specialty?
Specialty-focused organizations provide journals and annual conferences that keep their members abreast of the work and conversations going on among historians of the same sub-field. Membership in these organizations is particularly important for non-academic historians as we work apart from the scholars who drive the historiography. As it becomes more difficult for historians to formally publish their work, especially for those of us who lack institutional affiliation, we must keep abreast of the conversations in our field so we can keep our work relevant and know how to pitch ourselves to editors.