Once upon a time, I was doing the typical thing of going with what I was told worked or what I watched the engineers I had assisted do.

Specifically, I was recording piano with a pair of matching microphones in an XY pattern around the hammers. I knew about many approaches (another mic at the far end of the piano and then pan that mic over to the bass side of the stereo spread, pair of PZMs taped to the piano lid, throwing mics under, over, and in the holes, etc.).