The four-time Formula 1 champion retired at the end of last year after a stint with Aston Martin.
Still only 36, he has been linked with new racing opportunities just a year into his retirement.
"You can never rule it out, but at some point the time will be over,” Vettel told the German Press Agency.
“My age was not the issue and it was my decision to draw the line. But I didn't pull it to pick it up a year later.
"I have the privilege of spending more time with my family and children, that's a priority.
“Just as I have rediscovered the world in recent years, Formula 1, as big as it may be, has become smaller and smaller."
Vettel won 53 F1 grands prix, claiming four consecutive titles with Red Bull.
He was unable to replicate his success after a big-money switch to Ferrari, but retired a legend of the sport.
Asked about his next career plan, Vettel said: "I'm curious about that myself.
"But that was exactly my intention: not to take on the next task directly or to get into the next cockpit and first get to know the side of me that can try everything and has time.
“I haven't had that in the past. I live in a phase where you can feel yourself a little differently, discover yourself.
“At the same time, I really enjoy spending time with my family. That's why I can't give this dream answer about what will be in the future."
The environment and sustainability will continue to be important to Vettel.
“All the things that have been bothering me in the last few years will continue to bother me in the future and it could maybe go in that direction," he said.
Recently the German driver has been linked with a test for the British Jota team in the World Endurance Championship.
They are led by team principal Dieter Gass, a fellow German, who previously ran Audi Motorsport.