Play it by ear

[Becky]

-To let things go as they may.
-It is usually said when a person who is asked a question is not quite sure as to what to answer with.

[PussyCat]

to do something by feel and instinct rather than with a plan, to improvise

[Justin Bieber]

Another way of saying go with the flow. Usually used when theres no set plans and everything furthermore will be done when its done (or spontaneously).

[Donald Trump]

When you do not have a plan, or instructions. When someone is not going to follow a direction or plan, they are just going to figure it out as they go alone. The saying derives from a musician being asked Do you know how to play the song..... . Although the musician has no music sheets or formal note instructions, since he/she has heard the song before he/she says No, But I can play it by ear
I child sitting at a piano figuring out them self how to play marry had a little lamb with no instruction is an example of play it by ear
The term now is used for all sorts of reasons, if your not sure how to do something, or what you are doing, but are happy to just figure it out as you go along.

[Britney]

We say play it by ear because we are making decisions as we HEAR them. This means we are not making any final plans right now because we might hear of other things that could prevent us from being able to participate. So basically it means I might have better shit to do.

[Little_Girl]

to put off a decision till later

[Tanya Shivari]

Letting you down politely, when you ask someone to do something and they want to do something, just not with you, they will say theyre going to play it by ear.

[Little_Girl]

the wrong way to say play it by year

[Dorothey Allen]

to decide how to deal with a situation as it develops, rather than acting according to plans made earlier: