stop doing something while one is still at the peak of one’s ability
一个人仍在其能力高峰时停止做某事

例如，当约翰在赌场赢了一千美元，他的朋友告诉他见好就收。他不听，最终输掉了比他赢的多得多的钱。
Example： When John won a thousand dollars at the casino, his friends told him to quite while he was ahead. He didn’t listen and ended up losing much more than he won.