It's easy to be wise after the event

It's easy to be wise after the event.

  (British, American & Australian) also It's easy to be smart after the fact. (American)
something that you say which means that it is easy to understand what you could have done to prevent something bad from happening after it has happened In retrospect I suppose we should have realised that she was in trouble and tried to help her, but then I suppose it's easy to be wise after the event. People often tell me they'd never have taken out a loan if they'd thought about it more carefully - but it's easy to be smart after the fact.
See also: after, easy, event, wise