IN April 1962 the Beach Boys recorded “Surfin’ Safari” and “409” at Western Recorders in Los Angeles; the demo tape soon became their first single on Capitol Records. The following month El Gran Combo formed out of the remains of Rafael Cortijo y Su Combo, a brilliant band that had come to symbolize the new Puerto Rican popular music: black, working-class, Cuban-influenced, tight and urban but rustic at the middle. In July Mick Jagger, Keith Richards and Brian Jones gave their first performances, as the core of a band called the Rollin’ Stones, at both the Marquee and the Ealing Jazz Club in London. And in November the Chieftains, a group of virtuosos who sought to play traditional Irish music in a new way — in precise, small-group arrangements — started rehearsing at the house of Paddy Moloney, the group’s leader.

These are some of the bands positioned to turn 50 in public this year and promote their golden jubilees down to the ground, through tours or new recordings or both. (All but the Stones have announced their plans.)

Your automatic response might be the fact-checking ones: “Fifty years? Is that correct? How many original members remain?” The second might be emotional: “They’re only in it for the money,” or “Good for them; they don’t want to stop.” The third — and this is where the response gets interesting — may be: “That’s quite a list. Wonder what they have in common?”

These are among the first living pop bands to turn 50. Popular musicians have become a different species, healthier and more adaptable. So have their audiences. (So have their lawyers and publicists.) There was a time when pop was predicated on the notion of being disposable; listeners revised their tastes quickly. Now we keep our teenage ears into retirement age.