Ninety-four-year-old Kenny and 91-year-old Selma know the key to a successful marriage.

Who wouldn't want to listen to their advice? They've been married for 72 years.

When the couple couldn't make it to their grandson Mike Bender's wedding in Santa Barbara, the two decided to toast the newlyweds via webcam. More importantly, they shared the five key tips to making a marriage last, and their comedic well wishes went viral.

"Hello, everybody!" the couple say in unison as the video begins. "Mike and Sue, I'd love to give you five tips to a warm and healthy marriage."

The couple says it's all about being good to each other, making sure you have food in the fridge, help out financially and traveling. Oh, and no arguing.

"Just don't argue with each other!" Selma says.

"I don't argue with you!" replies Kenny.

The arguing continues. However, according to Stephanie Coontz, director of research at the Council on Contemporary Families and author of "Marriage, A History: From Obedience to Intimacy, or How Love Conquered Marriage," the couple pretty much has it right.

"Well, I would say that four out of five isn't bad! They have actually a much more modern approach," Coontz told ABC News. "The one that's wrong is, 'Don't argue.' It turns out that bickering is not bad for a marriage at all because it means you're negotiating and going back and forth."

Bender, who edited the video, ended up showing the video to wedding guests at the reception.

"That's the classic of my grandparents. That's their back and forth," Bender told ABC News. "People were cracking up. It was definitely, I would say, it was the highlight of the wedding for them."

Bender always knew his grandparents were characters and has used his website to share their story. Just last year, Selma and Kenny shared via webcam how their journey together began in New York City with a first date that didn't go so smoothly.

"We were sitting there and I'm watching the movie and all of a sudden his hand goes around my shoulder, and he starts to creep down," Selma explained. "And I said, Excuse me? Just a minute. And I got up and I got the usher and I said that man is touching me … so the usher made him leave the theater. But of course we laughed about it afterward."

Now the couple lives in Florida, with Selma working as a manicurist and Kenny in a deli shop. To Bender, he believes laughter has been the key to his grandparent's successful marriage and plans to take their advice to heart.

"I think there's some real logic to what they were saying," Bender said. "In marriage the most important thing is that you're laughing, and that comes out at the end of the video."