Just a few more comments:
There is a very real phenomenon called "reenactor burnout." People start out as "farbs" and if they stay in the hobby, they try to become more and more authentic. But this usually lasts a few years, until they get tired of the whole thing. Then they seek other time periods or drop out entirely.
Of all the time periods I've reenacted, I have to say that WWI was the most rewarding "immersion experience." WWI is by reenactors, for reenactors (no distractions from spectators). The events are run on a 24-hour basis, for an entire weekend. They're in a fixed location, so that both sides can improve their trench systems to a high level of authenticity. (The organizers have even been known to dress some rotten meat in uniforms, and place it out in No Man's Land, among the barbed wire and shellholes.) It gets really interesting when you have to go through a simulated gas attack. (No gas mask, you're dead. By convention, colored smoke is "gas" while white smoke is... smoke.) Add the pyrotechnics -- including parachute flares at night -- and the cold, wet weather, and you really get the feeling you're on the Western Front.
American reenacting is quite different from European, especially British, reenacting because of the strong emphasis on safety on this side of the Atlantic. The British treat their reenactments like rugby scrums and expect to get hurt. But even in America, reenacting is not entirely free of risk.
