Also, just because I think it's worth noting, drinking kava throughout the day usually doesn't make me feel very good (only speaking from fairly limited experience on this). Because your appetite is suppressed with kava, it's hard to eat normally and that leads to issues. Also, the diuretic effect is something you have to worry about even more than normal. Plus, I just got too foggy headed for it to be anything beneficial. I find that the anti-anxiety effects can last for a day, sometimes two without losing mental clarity whereas higher consumption just leads to more fogginess (for me).
I love Vekta's description of it being a "shield", it is for me too and that effect can last longer than the 'initial' kava experience.