In the past composers wrote 'pieces' of music. More important pieces were called'works'. Nowadays, however, most composers write minutes. Phone up any professional composer and ask how'r'ya doing? and nine out of ten will say something like: "Terrible/ awful … I've only written 4 (or …..) minutes and I have to write … minutes!"
We're all commissioned to write minutes - like so many feet of wallpaper. Imagine this:" We loved your Jupiter Symphony Mr. Mozart, but it's 3 minutes less than we commissioned."
Fortunately most composers cheat a bit, and most commissioners don't sit with stopwatches in their hands.1000 bars is not 1000 bars long. I stopped when the piece was finished. However it did turn out to be exactly 4'33" in duration.
What the piece itself is about has nothing to do with its title or length.