Better safe than sorry

चिन्तनीया हि विपदाम्
आदावेव प्रतिक्रिया ।
न कूपखननं युक्तम्
प्रदीप्ते वह्निना गृहे ॥

One should foresee the effects of a problem and decide how to react to them well in advance. It is improper to dig a well when the house is on fire.

Prevention is better than cure.
A danger foreseen is half avoided.
Better safe than sorry.