The Slackers’ annual December show is something of a company holiday party for New York ska fans, drawing folks from throughout the tri-state area to dance to many of the same tunes they’ve loved for decades. This happy tradition remains mostly unchanged, albeit this year with an addition that was a sign of the times: a mask that covered saxophonist David Hillyard’s face and mouthpiece. Their rollicking Irving Plaza performance included many longtime favorites, a harmonica-laden dub tribute to the late Lee “Scratch” Perry, extra boogaloo spice on their 1997 song “Fried Chicken” and a handful of classic reggae instrumentals woven into song bridges, for the true heads.

The Slackers remain at the top of their game and exist as a rarity among independent bands, especially ska and reggae groups: six working musicians who regularly play more than 150 dates a year in the United States and abroad, and who manage to sustain regular creative output and a fan base without major label support, charting singles or massive lineup changes.

“I remember there being a moment where we had found this vein of truth and goodness. And it had been somehow passed over by the rest of the world. They missed the ska beat, somehow,” singer and keyboardist Vic Ruggiero says over the phone from a tour stop in Berkeley, Calif., his signature Bronx accent coming through loud and clear. “It was our job to be like, ‘We’re going to pick up where those guys dropped the ball.’ ”

Along with contemporaries such as Hepcat and the Pietasters, the Slackers have managed to hold on to that vein of goodness — ska and reggae — despite marked ebbs and flows in popularity. It’s arguable that no one has done so with as much verve while also transcending the genre they love. “They are the total antithesis of this horrible mozzarella stick [joke] that floats around about ska,” says Marc Wasserman, author of “Skaboom! An American Ska & Reggae Oral History.” “Their songs are about real darkness, depression, anger, sadness and loneliness, and some of the political songs as well are pretty vibrant.”

A year without touring thanks to the pandemic forced the Slackers, whose members are now in their 40s and 50s, to readjust their regular plans. But they didn’t sit on their hands; “we pivoted on a dime,” says guitarist Jay Nugent, the “newest” member, who joined in 2004.

They finally put all of their merch online, and they did weekly group quarantine sessions and live streams where Nugent discussed his production equipment, Hillyard played sax and trombonist/singer Glen Pine showed his grandma’s soup recipe. The Slackers also recorded about 20 new songs and cut their 15th album, “Don’t Let the Sunlight Fool You,” for Pirates Press Records. Due in March, the album has a familiar Slackers vibe, while also foregrounding the band’s non-reggae influences.

The band managed to play more than 50 shows in 2021, once touring picked back up. Reflecting upon the time off the road before that, the members recognize it now as a much-needed break that allowed them to spend time with their family, getting physically and mentally healthy and finding a new creative spark. It also uprooted complacency and forced some of them to recognize what they had been taking for granted.

“All of a sudden, the rug is pulled out from under you, and you don’t have this anymore. You really miss it,” Pine says of performing. Adds drummer Ara Babajian of the current tour: “There’s a lot of gratitude happening right now between us and our fans. They really appreciate that we’re taking the risk of getting out on the road again, especially with this new variant.” The Slackers are being as careful as possible, and although there’s a lot at stake, “the rewards of playing a great show and connecting with the audience right now is greater than it’s ever been.”

The Slackers first formed in 1991 in New York. While Ruggiero and bassist Marcus Geard are the only two “original” members remaining, others in the lineup were part of the same overlapping scene. (Hillyard moved from California and joined the band in 1993.) The Slackers spent years playing small gigs and rehearsing in a Lower East Side basement before releasing “Better Late Than Never” in 1996, then followed that with three albums on Hellcat Records, the label co-founded by Rancid’s Tim Armstrong. They’ve since released around a dozen studio albums, three live albums, and a handful of singles and EPs.

While they existed concurrently with the third wave of ska in the 1990s, which saw bands such as Reel Big Fish and the Mighty Mighty Bosstones become alternative radio breakout stars, the Slackers were misfits. They favored traditional 1960s ska and slower, grooving rocksteady, while their contemporaries infused punk into their songs. They also didn’t shy away from imbuing their records with plenty of other influences — jazz, soul, boogaloo and even country — and they always emphasized songwriting, which, over the years, has become a more collective process.

The ska boom was short-lived, and the scene became basically nonexistent into the early 2000s. That’s when the Slackers doubled down on building a grass-roots following by hitting the road nonstop. “We’d play anywhere and everywhere,” Pine says. “We learned that if you can give it your all and win those couple people over, they’ll bring their friends next time.”

Although there are certainly new fans — people who came to the band as part of a renewed interest in ’90s music, teens who first saw the band with their Gen X parents — the Slackers’ base has stayed with them all the way through. Those early fans have become lifelong listeners, turning out year after year whenever they come to town.

“They’re sort of like the Grateful Dead of ska,” Wasserman says, adding that there are bootleg Slackers albums, and you’ll often hear people requesting obscure songs at shows. Slackers fans often occupy a particular place in the larger ska community: “We’re an independent band and independent scene. Not everybody in the ska scene is a huge Slackers fan, and not everybody who’s a huge Slackers fan is into ska,” Geard says. Because they tour so much, the Slackers can keep up with their fans’ evolving tastes. “When their tastes change, our tastes change and vice versa,” Ruggiero says.

Still, the Slackers have become the elder statesmen in American ska music, setting the stage for a new generation of musicians and a thriving scene. They’ve seen bands grow up around them, including L.A.’s the Aggrolites, who have been the opening act for much of the 2021 Slackers tour. Many so-called fourth-wave ska groups were teenage Slackers fans and now share stages as adults.

The Slackers keep their music and performances fresh by playing a different set every night, improvising and stretching out tunes. The Irving Plaza show was bookended by the swinging, Skatalites-style “Prophet” (from their debut album) and a new twist-and-shouty single, “Nobody’s Listening.” They are also known to do all-request and single-album shows, booze cruises and festival gigs. Multiple members have side projects — among them, Hillyard’s Rocksteady 7 ska and jazz group, Ruggiero’s Bob Dylan-esque solo work and Nugent’s new label, Old Neighborhood Music — keeping them busy during the Slackers’ offseason.

Thirty years on the road isn’t without its challenges for a group of self-described brusque New Yorkers with strong personalities now squarely in middle age. Being in the Slackers often feels like a marriage, and, “like any family, we have to have workarounds for how things are going to continue to operate,” Geard says.

The Slackers long ago learned to give each other space on the road. They travel in two vans; some members prefer to stay with friends instead of in hotels. Although Hillyard enjoys getting to a venue early to prep, Babajian prefers to relax, and others take their time ambling around town, visiting friends and buying records. The love of a good meal unites the band members — the pozole at Berkeley’s La Mission was a shared highlight this tour — though they don’t always eat together.

They also have had to navigate a variety of lows, such as dealing with bandmates who are in bad moods and who know how to push each other’s buttons, as well as managing trouble at home. Then there are the more existential issues for touring musicians, including commitment and sacrifice. Through it all, somewhat shockingly, the Slackers are still friends and not just bandmates.

“We’re probably better friends now than we’ve ever been. And I think it’s due to having had a year off the road,” Babajian says. “It was nice that the train slowed down for a little while. You realize that it’s going fast at the time, but you don’t realize how much damage it’s doing to your personal life, how neurotic it’s making you.”

However, it’s the pandemic — not age — that will probably bring the most change to the Slackers’ future. The band usually does at least one European leg a year, but the coronavirus has made planning international tours tenuous. They’re also jockeying for stage space with other groups whose performances were postponed. It’ll take years to sort out the mess the pandemic has wrought on musicians, so Hillyard hopes to do 50 to 75 shows in 2022 at slightly bigger venues than they usually play. “It’s modest, but it’s actually kind of hard to achieve,” he says.

The Slackers are spread out across the country now — only Hillyard and Nugent live in New York — but back at Irving Plaza, there’s a distinct feeling of homecoming. Fans who attended the show despite spiking coronavirus cases were visibly euphoric, though the crowd was thinner than at previous holiday shows. At the end of their 2021 tour, the Slackers provided what may be the final, cathartic hurrah before the virus disrupts live entertainment once again.

Still, there’s no biopic-style high point for the band. “The Slackers have funny stories: dangerous situations, excitements, vans breaking down and exploding, cops, chase scenes, kicking down the promoter’s door to try to get paid at the end of the night. It’s hard to navigate what’s the best,” Ruggiero says. “The high point is that we got the van and we never stopped driving.”

Health permitting, expect to catch the Slackers on the road for the next 20 years.