It never gets easier for Chandra Wilson to say goodbye to her Grey’s Anatomy costars.

The actress, 57, has been part of the long-running medical drama since it premiered in 2005. Over the past two decades, she’s watched plenty of stars come and go, including Sandra Oh, Patrick Dempsey, Justin Chambers and, most recently, Kevin McKidd and Kim Raver, who departed in the season 22 finale.

“I’m always sad when I lose my babies, because to me, they’re all my babies,” the actress tells PEOPLE. “I keep waiting for the days they come back and play with us.”

Season 23 premiered on Oct. 15, following a season 22 finale in which McKidd and Raver bid farewell to their long-running roles as Dr. Owen Hunt and Dr. Teddy Altman. Their characters, an on-again, off-again couple, decided to move to Paris together for Teddy’s work.

But as Wilson tells PEOPLE, there is an “ebb and flow” to the series as new faces arrive and longtime cast members depart.

“You swear that when someone leaves, that’s it, we’re done,” Wilson says. “And then our new babies come in and then we start investing as an audience, as well as the other characters on the show that then have new people to get used to.”

This season, James Wolk joins the cast as Dr. Seth Norton, bringing a new perspective to the halls of Grey Sloan Memorial Hospital. For Wilson, that constant turnover is part of what makes the show feel authentic, as saying goodbye to colleagues and welcoming newcomers somewhat reflects the realities of working in medicine.

“It is you come in, you learn, you train so that then you can move forward into whatever the next thing is,” she says. “Very few people then continue on their attending career in the place where they were a resident.”

While cast exits remain bittersweet, Wilson says it’s “always exciting” to welcome new cast members to the show.

“We definitely feel that sense of how iconic a show we are when we see it through someone else’s eyes and they step in and they’re wondering, ‘What in the world am I gonna contribute and what is this?’ ” she says. “I love being the one to say, ‘You’re here, you made it, so don’t worry about that part anymore.’ Now, you focus on what is it now that you’re gonna add to this beautiful painting that we have.”

Over the years, many of the cast members who have left have made surprise returns, including T.R. Knight and Dempsey, whose deceased characters returned as Meredith saw them in dream sequences in season 17.

Wilson welcomes those reunions, too, viewing them as another way to celebrate the show’s history and the characters who helped shape it.

“It’s kind of like once you’re there, you’re there, dead or alive, child. We don’t care. Come on back home,” she says. “Our audiences appreciate it [and] the fabric of our show appreciates us seeing all of our past characters. I just love it.”

Wilson and James Pickens Jr., who plays Dr. Richard Weber, are the only two original cast members who remain on the show in a full-time capacity. (Pompeo began scaling back her role during season 19, but remains part of the cast.)

Speaking about her off-screen dynamic with Pickens Jr., Wilson says they recognize the responsibility that comes with being among the few remaining links to the show’s original era.

“I appreciate him so much. And together, we are very aware of the tone that we set when we’re on set because, you know, people call it an iconic show,” Wilson says. “It doesn’t matter if we just think that we’re just going to work every day. We appreciate the fact that that is what it is and that’s how we’re seen, and we wanna honor that to the best of our ability.”

“He and I are very, very sensitive to honoring that and making sure that people have something to be proud of when they come to work,” she continues.

Grey’s Anatomy airs Thursdays on ABC and is available to stream on Hulu the next day.