This October, The Oak Ridge Boys will celebrate its 50th year with its current lineup, with Joe Bonsall being the last to join the group, in October of 1973. The group, which also includes William Lee Golden, Duane Allen and Richard Sterban, likely never imagined that they would all spend five decades together, an almost unheard of feat, in any genre of music.

Bonsall, who turned 75 earlier this year, is also the youngest member of the group, by five years. Allen and Sterban are both 80, while Golden turned 84 in January.

As expected, health challenges have impacted them in recent years, including ongoing leg issues with Bonsall. After so many years together, Bonsall admits he recently acknowledged that there is an inevitable day when at least one of them will be unable to continue life on the road.

“I sat in the back of the bus with Duane Allen one day, and I said, ‘Duane, what if I can’t do this anymore?’” Bonsall recalls to Billboard. “And Duane said, ‘Then we go home.’ I like to think that it would still go on. But I don’t know for sure that it would.”

Bonsall was singing with The Keystones in 1973, when he was invited to leave that group and become part of The Oak Ridge Boys, a popular gospel quartet at the time.

“I don’t know that I ever thought about it much, except for the fact that I love The Oak Ridge Boys and holy cow, they’ve offered me a job,” Bonsall shares. “It was a big deal to me because I loved that group. They were a cutting-edge gospel group at that time.”

Cutting edge, indeed. The Oak Ridge Boys soon made the switch to country music, becoming one of the first groups to make concerts an experience by using lighting and, at the time, state-of-the-art technology.

“Now everybody uses the moving, computerized light system,” Bonsall says. “But back then, nobody had seen it before, and I’ll tell you what: when we were out there singing on that stage with the lights moving and the smoke flying and the lasers hitting, that was big-time rock’n’roll.”

The Oak Ridge Boys also fought, and fought hard, to not have a lead singer, another concept that hadn’t fully been done, at least within country music, before them.

“The Statler Brothers, they have one lead singer that had probably 90 percent or more of all the leads,” Allen says. “And Alabama — Randy [Owen] has about all of them, [like] most every group that’s ever come out of country. In fact, we had to fight with our label and producers to get leads for the other people from the very beginning, and we finally got leads on hits by everybody.”

50 years later, The Country Music Hall of Fame members are, rightfully, proud of their heritage and their legacy, and their tenacity, after so much time together.

“When we sing on a note, we’re not like barbershop harmony, which seems almost perfect harmony,” Allen boasts. “When we sing, there’s an edge to it. Instead of harmonizing in perfect harmony, we’re more like four Peterbilt trucks headed right at you on an interstate highway.”

The Oak Ridge Boys have more than earned the right to at least ease off their touring schedule a bit, and enjoy more time for relaxation. It’s a concept that is all but foreign to them, which is why they keep pushing themselves to do more.

“We’re the old guys on the block, but we just don’t know how to slow down,” Bonsall recently told Fox 13. “The Oak Ridge Boys sing. That’s what we do. And we’ve been able to plan every aspect of everything we do. Except we’ve never been able to plan how to slow down, let alone stop.”

Find all of The Oak Ridge Boys’ music and a list of all of their upcoming shows at OakRidgeBoys.com.