Let well enough alone.

　　To muddle along.

　　eg：It's not easy to find a job, so let well enough alone with what you have now.

　　中英俚语俗语来源：陶宗仪·辍耕录：“寒号虫至深冬严寒之际，自鸣曰，得过且过。”

　　同义词：马马虎虎 Fair to middling.

　　反义词：一丝不苟 Dot one's i's and cross one's t's.