Pepper, appearing in the refrain (B–2–3), in a tonicization of VI in the bridge (B) and, as musicologist Walter Everett puts it, "[in] the wide array of jaunty chromatic neighbors and passing tones comparable to those in McCartney's dad's 'Walking in the Park with Eloise'".

[citation needed] Supporting instruments include the piano, bass, drum set, tubular bells and electric guitar.

[10] On 20 December, McCartney, Lennon and George Harrison overdubbed backing vocals and Ringo Starr added the sound of bells.

"[20] Martin recalled, "I remember recording it in the cavernous Number One studio at Abbey Road and thinking how the three clarinet players looked as lost as a referee and two linesmen alone in the middle of Wembley Stadium.

[28] Everett comments that the protagonist of "When I'm Sixty-Four" is sometimes associated with the Lonely Hearts Club Band concept, but in his opinion the song is thematically unconnected to others on the album.

"[36][37] Peter Clayton of Gramophone magazine characterised the song as a pastiche of George Formby, but added it has "a kind of gentle affectionateness about it – and a certain meaty substance – which raise it well above mere kidding".

"[39] In Richard Goldstein's scathing review of the album for The New York Times,[40] he said that the song is not mocking in its tone, but complained that "an honest vision is ruined by the background which seeks to enhance it.

"[41] In his book Revolution in the Head, Ian MacDonald describes the song as being "aimed chiefly at parents, and as a result got a cool reception from the group's own generation".

[42] He adds that the song borrows heavily from the English music hall style of George Formby, while invoking images of the illustrator Donald McGill's seaside postcards.

[43] He says the music hall atmosphere is reinforced by McCartney's vocal delivery and the recording's use of chromaticism, a harmonic pattern that can be traced to Scott Joplin's "The Ragtime Dance" and The Blue Danube by Johann Strauss.

[46] Walter Everett agrees with Riley's description, adding that "this penchant for the audience-charming vaudeville sketch led to McCartney preferences that Lennon detested the most.

"[16] BBC Music critic Chris Jones describes the song as "pure nostalgia for his parents' golden age" and cites this as an example of Sgt.

[47] According to MacDonald[18] and Lewisohn:[48] The Beatles Additional musicians On the occasion of McCartney's 64th birthday in June 2006, a month after the singer's separation from his wife Heather Mills, Paul Vallely of The Independent wrote an appreciation that focused on the song's message.

Describing McCartney's birthday as "a cultural milestone for a generation", Vallely commented that the widespread support for the former Beatle and corresponding derision of Mills "tells us more about us than it does about her".

[50] In The New York Times, Sam Roberts likened McCartney's failure to fulfil the song's promise of retirement-age contentment with Mills to America's divorce rates and other socio-economic problems afflicting citizens in their sixties.