ST.LOUIS — California punk rockers the Offspring, with more than 20 years in the game, don’t harbor concerns over how to keep music fresh during constantly changing times.

Instead, the Offspring, which debuted in 1989 with “The Offspring,” keep forging ahead.

The band’s lead guitarist and backing vocalist Noodles said that “as far as connecting with younger audiences, just doing what we’re doing keeps us young. Playing for a living has kept us young all this time. The first 10 years, we did it as a hobby. ... In 1994, the doors opened and everything really changed.

“And as we made records, we kept pushing ourselves to keep it young and fresh.”

Noodles said classic bands such as the Ramones and AC/DC were able to “make the same record over and over and it still sounded good, but we’re not a band that can do that.”

These days, the band keeps itself relevant with its new album, “Days Go By,” its first since 2008’s “Rise and Fall, Rage and Grace.”

Explaining the long absence between albums, Noodles said, “We don’t really write new music on the road while touring. We spent a year touring after the last record and kept touring every summer. And then when we go into the studio, it’s really hard.”

What makes getting in the studio harder is that the band is pickier than ever.

“We wanted to make sure we’re doing something good and not doing something that sounded like something before. We want to keep pushing ourselves,” Noodles said.

That was the case with the title track, “Days Go By,” which he says changed over a two-year period.

“The structure of the song changed a lot,” Noodles said. “We felt it could get better and better. The lyrics changed. (Singer Dexter Holland) wanted to write something a little more hopeful. He changed it so it was more about people suffering in the economy, people struggling but hanging in there because things will go better.”

He described “Days Go By” as a varied album, with a song for every day of the week.

“ ‘Days Go By’ is a straightforward rock song,” Noodles said. “ ‘Cruising California’ is our stab at a pop song. ‘OC Guns’ is a reggae song with some mariachi stuff.”

Still, for fans who just want vintage Offspring, “there’s plenty of fast, aggressive, melodic punky songs, the kind of songs that made us want to be in a band in the first place.”

The Offspring will perform at 7 p.m. Sept. 22 at the River Stage at Penn's Landing, Philadelphia. Visit www.livenation.com for more information.