Would you share your definition of maturity and the processes to become mature?

Watching people and seeing my own pathway to "grey hair", I have often thought about the question, 'what is maturity and when will we know we arrived/achieved?'

What ideals wait upon persons who seek maturity? Yes, I know; maturity varies and is not necessarily linked to body age. Given wide variances in human experiences, what could you say that defines maturity.