Better late than never:

亡羊補(bǔ)牢

例句：  

I'm sorry my gift came late, but better late than never, right?

很抱歉我的禮物送晚了，但總比不送好，對吧？

Save / keep money for a rainy day:

以備不時(shí)之需

例句：

You should keep some money for a rainy day. 

你應(yīng)該存一些錢以備不時(shí)之需。

Look ahead:

未雨綢繆

例句：     

I'm trying to look ahead at what might happen and be ready to handle it.

我打算未雨綢繆，作好應(yīng)對準(zhǔn)備。

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