it's easy to be wise after the event
It is far easier to understand how something bad could have been prevented after it has already occurred. I never would have bought this car if I had known it needed so much work done to it. Well, it's easier to be wise after the event.
It is easy to be wise after the event.
Prov. After you see the consequences of a decision, it is easy to tell if the decision was good, but it is also too late, since the consequences have already happened. Jill: I should never have invited Aunt Betsy to stay with me; I haven't had a peaceful moment since she got here. Jane: Well, it's easy to be wise after the event.