self-development 
noun [mass noun]
The process by which a person’s character or abilities are gradually developed: graduates have stressed the value of their courses for self-development...
- The cognitive processing of needs also results in the individualization of motivation which is related to the ability of self-development and of self-regulation.
- Self-cognition is the initial stage of self-development in the process of officers' military professional training.
- The final pillar of the Army's leader development system is self-development.