The two "All my life"s in the backing vocals in the choruses are sung to phrases that span large intervals (sixths) and include large note values (three whole notes each). Between those features and the fact that "life" is sung with a melisma both times, there's a musical sense of the encompassing nature of "all." Here's the notation for the first "All my life":
The second "All my life" has a peculiar rhythm at the beginning that I can't seem to suss out (so the dotted half note at the end of this first phrase might be wrong), but aside from that, it's fairly similar.
The other thing I noticed (and confirmed to-day) is that the guitar solo (~2:07) starts with a recurring phrase from the guitar solos in Paul McCartney's "Maybe I'm Amazed," just adjusted for key and with some changes in tempo. The phrase in "All My Life" also doubles a note.
In "All My Life," the guitar solo begins with:
E|---5-7-5-7~9-9-7-5-----|
B|-7-----------------7-5-|
The recurring phrase in "Maybe I'm Amazed" is:
E|---1-3-1-3~5-3-1-----These phrases seem too similar for this resemblance to have been coincidental. Because Jeff Lynne workt with Paul McCartney (although long after "Maybe I'm Amazed"), I think this might be an intentional similarity.
B|-3---------------3-1-
