The central idea in the poem is that life is full of decisions that you can't undo, so choose wisely. The roads we choose to take are equally as important as the roads we overlook. Mixed criticism exists about the poem, debating whether Frost is saying that taking the less traveled path was wise or foolish. Some read the poem with a negative connotation, specifically when he states "with a sigh," and take it to mean that he regrets his decision to travel the road not taken. Others read it as a sigh of contentment, signifying the speaker's satisfaction with his choice. Regardless of how you choose to interpret it, the message remains the same- you can't go back and change the choices you make, so choose wisely.
I think the message is: no matter how much you deliberate, how far you look down the path, some decisions will take up to whole life time, full of deliberations and regret.