at thirty, one stands on one's own; turning thirty and becoming independent
A set phrase from the Analects of Confucius, used to express the idea that by age thirty a person should be established and self-reliant. Often quoted or referenced in discussions about maturity and life milestones.
The phrase 'at thirty, one stands on one's own' is a passage from the Analects.
He put 'at thirty, one stands on one's own' into practice and started his own company.