You’re going to be hearing a lot about 50th anniversaries this year.PBS’s American Experience has a two-hour program called 1964 that premiered last week. It includes such milestones as Barry Goldwater’s presidential campaign, which though unsuccessful set the stage for a conservative political revival; the passage of a landmark civil-rights law and the conflicts around it; the Tonkin Gulf resolution pushing the U.S. more into war in Vietnam; a young boxer named Cassius Clay becoming heavyweight champion (and changing his name to Muhammad Ali); the anthemic pop song Dancing in the Streets; the escapism of Frankie-and-Annette movies; the debut of the Ford Mustang; and the Beatles’ arrival in America.The Beatles will also be celebrated on CBS, which has announced a two-hour February special marking the Fab Four’s first appearances on The Ed Sullivan Show on Feb. 9 and 16, 1964.I await prolonged tributes to the Pop-Tart, which also dates to 1964, and the TV show Jeopardy!, which turns 50 in March. You know you’re getting old if playing “Jeopardy!” at home started with deciding who would be Art.The events being marked are important historically, culturally or both — and one can make the argument that 1964 signaled huge change. Indeed, the PBS program notes that both Bob Dylan’s The Times They Are A-Changin’” and Sam Cooke’s A Change Is Gonna Come date to that year. Change, according to Cooke biographer Daniel Wolff, was a reaction to another Dylan song, Blowin’ in the Wind, which had been a hit for Peter, Paul & Mary in 1963. Cooke performed Change on The Tonight Show just days before the Beatles appeared on Sullivan. Cooke did not live to the end of 1964, shot in a controversial motel incident in December, not long before Change was released as a single.See what happens when you drift onto Memory Lane?At least, what happens if you are old enough to remember the Beatles on Sullivan or that Art Fleming was the first host of Jeopardy! I’m old enough for both those things and more. But turn to someone younger and ask him if he even knows who Ed Sullivan was.My colleague Malcolm Abram argues that the focus on ’64 is at least partly a result of baby boomers’ skill at navel-gazing. A similar argument could have been made last year, when the air was full of 50th-anniversary contemplations of the assassination of John F. Kennedy. While, again, there were historical implications, there was also the underlying assumption that it mattered emotionally to boomers and those older, who could remember when and where they heard the news of the assassination.But our age determines some of what matters to us — how much we care that 2014 is 70 years after D-Day, or that Playboy magazine is celebrating its 60th birthday.For younger folks, the events already mentioned are just history lessons. So are the Beatles, really, to anyone who doesn’t remember being told to get a haircut, let alone that a band could be considered radical even when all its members wore jackets and ties.Consider some other occasions with anniversaries this year. Revisiting Jeopardy!, for one, it was 30 years ago that Alex Trebek became host, the subject of Saturday Night Live parodies, and the only star of the show that a generation has known firsthand.It was also 30 years ago that Ronald Reagan further cemented his place in American history with a landslide election win over Walter Mondale. Reagan also name-dropped Bruce Springsteen, who in 1984 was riding a series of hits from his Born in the U.S.A. album. Reagan, apparently alluding to the album’s title track, saw a message of hope akin to his own “Morning in America” campaign ad. But the song was actually bleak and despairing, and Springsteen biographer Marc Dolan has argued that Reagan’s action so concerned Springsteen that the musician became more explicitly and publicly political.While Springsteen himself is considered geriatric by some, this is also the 20th anniversary of the death of Nirvana’s Kurt Cobain, still iconic to many fans and musicians.And it was 20 years ago that the Pretenders released I’ll Stand by You. In the notes for the Pretenders’ Pirate Radio collection, singer Chrissie Hynde concedes the song’s resonance.“I was embarrassed by this song because it was so intentionally commercial,” said the Pretenders’ leader, who co-wrote it. “But I played it to some girls I knew from the boxing community and by the end of it they were both in tears. So I guess it moved them.”And a lot of other people. It became a huge hit, recycled for weddings and sundry TV events.On television, 1994 was the year of The Real World: San Francisco, the third season of the MTV series and the one most famous for its inclusion of Pedro Zamora, a gay activist with AIDS. Kate Aurthur of Buzzfeed.com has noted that from its premiere in 1992 The Real World was committed to including gay people and was “life-altering” in presenting young, cool gay people on TV. But Zamora was even more moving, and not only because his death in late 1994 was strongly personal to people who had just been watching him on the program.“Either by accident, because he was a visionary, or both, Zamora also decided to marry his boyfriend Sean Sasser in front of the Real World cameras,” Aurthur wrote. “It was years before the marriage movement became the next frontier for LGBT rights, but Zamora and Sasser — so sharp in their white Oxfords during their commitment ceremony — still represent many people’s first image of what a gay wedding would look like.”But, again, the importance of that may depend on where you were in your life in 1994. It determines, too, whether 1964 matters at all.