I don't much like the word, really. I know what they mean, but it's... well... a bit icky and New Age. To me, the most important milestone in a person's development as an adult is a particular realization about the nature of one's own being. Specifically, it's the recognition that there is no absolute entity called "myself" -- it's recognizing oneself as the source or matrix of one's own experience, rather than some "thing" or object in a world full of objects. This is not a belief, it's more basic than that: the world looks different to someone who knows for certain that they are not their personality or identity or self-image. There is a different mode of experience for daily life, one in which everything that happens seems to occur *inside* a sort of container that one might call "myself" -- this container includes everything normally considered external as well as internal. The dividing line between "me" and "not me" disappears, in a manner of speaking. Sometimes I call this "being yourself", because I don't like it when folks get all spiritual about it or start using words like 'enlightenment' or 'self-actualization' or 'true being' or 'transformation'. All we're really talking about here is losing certain illusions about who and what you are, so that a more integrated and unfragmented sense of being is apparent. To me, this is the main purpose of intellectual, emotional, psychological, and personal development: to keep struggling with the matter of your own identity until the puzzle and confusion start to break down and a clarity emerges that doesn't involve clinging to concepts about yourself. There's really nothing one need change about their life for this to happen, it's a matter of persistent inquiry and being willing to discard the many tempting false solutions which arise along the road.