适可而止见好就收
[shì kĕ ér zhĭ jiàn hăo jiù shōu]
It's called 'Shi Ke Er Zhi Jian Hao Jiu Shou' or 'stop while you're ahead.' It implies knowing when and stopping at the right time instead of pushing your luck too far; recognizing and capitalizing upon an opportune moment. The concept embodies wisdom, judgment, and self-discipline.