In terms of chords and melody, Stay Young has complexity on par with the typical song, having near-average scores in Chord-Melody Tension and below-average scores in Chord Complexity, Melodic Complexity, Chord Progression Novelty and Chord-Bass Melody.
Stay Young is written in the key of E♭ Major. According to the Theorytab database, it is the 7th most popular key among Major keys and the 11st most popular among all keys. Major keys, along with minor keys, are a common choice for popular songs. The three most important chords, built off the 1st, 4th and 5th scale degrees are all major chords (E♭ Major, A♭ Major, and B♭ Major). See the E♭ Major Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!