Westlife's 'What Do They Know' serves as a poignant reflection on the passage of time and the memories that define our relationship with the past. Recorded for the 2003 album Turnaround, the track exemplifies the group's signature blend of acoustic guitar, piano, and harmonized vocals that characterized their mid-2000s pop ballad style. The song explores themes of nostalgia and the realization that while the future remains uncertain, the lessons learned from history provide a guiding light. Its melodic structure and emotional delivery became a staple of the band's live performances, resonating with audiences who appreciated its universal message about cherishing experiences that have already occurred.