One full take, then layers.

About one. Pink Floyd recorded the core of “Echoes” in a single extended jam, then overdubbed and edited. There wasn’t a parade of discarded complete takes—they built it in sections.

The famous 23-minute piece came together from a few backing track attempts, but the band has said the basic structure was locked in early. The rest was layering, not do-overs.

So the answer is fuzzy, but fewer than you’d expect. The magic is in the editing, not the number of retakes.