SIMPLY PUT
Credit: NY  Times Crossword - May 12, 2013
David J. Kahn

Can you deflate this bloated bit of advice and rephrase it in as few words as possible:

The potential consequences of a plan or decision one cannot reverse should be carefully considered prior to the effectuation of the action - which action will set in motion events leading to an unavoidable conclusion.

Answer:

Look before you leap.