You can’t be too careful
Definition 1 of 1
Pro Tip 1/3Subtle Urgency
This phrase conveys a sense of important caution without causing alarm. 
She checked her passport’s expiry date repeatedly; you can’t be too careful with international travel.
Pro Tip 2/3Risk Aversion
This phrase is often used for situations where taking extra precautions is justified to avoid negative outcomes. 
I always back up my files twice. You can’t be too careful with digital data.
Pro Tip 3/3Slight Overreaction
Sometimes, it's used to acknowledge doing more than usual out of caution, not necessarily a bad thing. 
I installed a new alarm system and bought a guard dog. You can’t be too careful.