It comes from the idea of a musician playing a piece of music without sheet music, relying on their own intuition and experience to guide them.
Here are some examples of how it's used:
* "We don't have a definite plan for the weekend, so we'll just play it by ear." This means they will decide what to do as the weekend progresses.
* "I'm not sure what to say at the meeting, so I'll just play it by ear." This means they will react to the situation as it unfolds.
* "The weather is unpredictable, so we'll play it by ear and decide whether to go hiking." This means they will assess the weather conditions before making a decision.
Essentially, "playing it by ear" signifies a flexible and adaptable approach, where you are willing to adjust your actions based on the circumstances.