The Eagles 1975: Guitarist Bernie Leadon leaves, frustrated that the band's country rock is more country than rock. Joe Walsh joins and the next year The Eagles write and record Hotel California.
The Temptations 1968: Lead vocalist David Ruffin quits, objecting to their shift away from traditional soul. Enter the more accommodating Dennis Edwards. Within a year, 'Cloud Nine' wins Motown it's first Grammy Award and puts the group on the path to 'Papa Was a Rolling Stone'.
King Crimson 1969: Rock trio Giles, Giles & Fripp sell less than 600 copies of debut album The Cheerful Insanity of Giles, Giles & Fripp. One Giles brother (Pete) goes, Greg Lake arrives. A swift change of names and In the Court of The Crimson King is just around the corner.
The Beatles 1962: A unanimous decision is taken to sack drummer Pete Best. Ringo wasn't first choice as replacement - somebody called Johnny Hutchinson turned down Brian Epstein's job offer.
The Sex Pistols 1977: Glen Matlock quits and John Richie, aka Sid Vicious, is recruited. The new bass player's marked lack of ability is amply compensated by his general demeanour and a string of Top 10 hits ensues.
Def Leppard 1978: A pounds 50 per night pub band when Tony Kenning gives up his drum stool to the 15-year-old Rick Allen. Such is Allen's contribution, the band doesn't replace him when he loses an arm in a car crash six years later.
The Who 1964: Drummer Doug Sandom quits beat combo The Detours; the remaining members - Roger Daltrey, John Entwistle and Pete Townsend - are joined by a 'drunk dressed entirely in amber'. It is Keith Moon, and six months later they are The Who.
Bananarama 1988: 'The most successful girl group ever' lose one third of their original line-up when Siobhan Fahey is replaced by Jaqui Sullivan. The hits keep coming.
Depeche Mode 1981: Vince Clarke, who wrote most of their first album, leaves because he doesn't want to tour. With new synth player Alan Wilder the group travels to the USA, where they now sell out stadiums. .