It's hard to say. Last time I was really manic was in 2008. After that, I had some minor bouts with mania, balanced with equal doses of depression, from time to time. I did not do well in 2010-2011 and got fired from my job. Since then, though, I've been solid. I think the environment I am now in has helped me. The short answer, then, is six years. With medication. Usually. Sort of.