KANNAPOLIS, N.C. (AP) There was no final straw, no outside influence, no personal trauma that led Tony Stewart to set an expiration date on his NASCAR career.
Instead, the three-time NASCAR champion simply decided enough was enough.
''I think deep down you know when it's time to do something to make a change,'' Stewart said Wednesday in announcing he will retire from Sprint Cup racing following the 2016 season to wrap up a storied 18-year career in NASCAR's top tier.
If there was any doubt Stewart was at peace with his decision, he proved otherwise with a wide smile and his usual self-deprecating humor during a news conference that lasted nearly an hour at Stewart-Haas Racing.
He called the decision ''100 percent'' his choice, said the only pressure he received was from those trying to talk him out of it and he dismissed the idea that his personal struggles the last three years factored into his choice.
Stewart also tried to ward off any sort of retirement tour in 2016 like the one currently going for four-time series champion Jeff Gordon.
Gordon is feted at nearly every track with gifts to commemorate his career, and he visits with reporters almost week to answer questions about this farewell season. Stewart isn't interested in the same treatment.
''Let's establish this right now: I will not be coming to the media center every week to talk about it,'' he said. ''You can save your gifts. I've got enough rocking chairs at home. I'm not really that kind of guy. I'm content to go race and be around the racing community and the racing family and be around our fans. They can just send me a note from the track president and say, `Hey, thank you,' and that'll be sufficient for me.''
Stewart, who deeply loves dirt track racing, isn't getting out of the car for good, though. He said he will still race in some capacity after 2016, and with a soft smile answered, ''Maybe. Probably,'' when asked if he'll get back into a sprint car. Stewart has not raced a sprint car since August 2014, when his car struck and killed a young racer, Kevin Ward Jr., at a dirt track in upstate New York.
His planned departure is not a surprise. Stewart will be 45 next season, he hasn't won a race in over two years and has been privately working on finding a successor for the No. 14 Chevrolet all year.
Clint Bowyer, released from his contract with Michael Waltrip Racing because the team is folding at the end of the season, will replace Stewart in 2017. Bowyer has been looking for a one-year deal while Stewart runs his 18th and final Cup season. SHR also fields cars for reigning series champion Kevin Harvick, Kurt Busch and Danica Patrick.
The last three years have been trying for Stewart. The fatal incident with Ward last year took an emotional toll on him and he still faces a wrongful death suit from Ward's family. He missed the final third of the 2013 season with a broken leg suffered in a sprint car crash.
His passion for NASCAR racing has also waned in the last several seasons, in part because of an evolving rules package that he has struggled with. He is currently 25th in the points standings and failed to qualify for the Chase for the Sprint Cup championship for the third consecutive year.
Eddie Gossage, president of Texas Motor Speedway and a close friend of Stewart's, said the driver had discussed retirement with him ''over the last six or eight years.''
''I think he always viewed Cup racing as a job that helped him fulfill his passion for racing on dirt tracks, running world-famous Eldora Speedway or owning the All Star Circuit of Champions Sprint Car Series,'' Gossage said. ''I don't know anybody that loves racing more. He's a sure-fire, first ballot shoo-in for the NASCAR Hall of Fame.''
Harvick, who was lured to Stewart-Haas Racing by Stewart and won his first Cup title last season, has struggled to ''put my arms around'' Stewart's decision.
''I've seen Tony as my driver, my boss and my friend. But in the end I want to see him smile and be happy in his life. Tony has done a great deal for not only my family, but the sport that we all love,'' Harvick said.
Stewart has 48 Cup victories and is a lock for the Hall of Fame. The fiery Indiana native has been one of the most proficient drivers in racing, winning in every kind of series, from sprint cars to a dominant stretch in NASCAR where he reeled off at least one win in 15 straight seasons.
But the last two seasons have been filled with heartache and hardship on and off the track for Stewart. While no one would ever count out Stewart from winning one more race, he's no longer a regular threat to find victory lane. He last won a Cup race on June 2, 2013, at Dover International Speedway.
Stewart said he considered retiring at the end of this season, but stuck around for the fans and to try and win his first Daytona 500. He is also missing a Southern 500 victory at Darlington Raceway, and never won his beloved Indianapolis 500.
Still, he said he has no regrets, not even turning down Roger Penske's offer of an Indy 500 ride in 2013. AJ Allmendinger ultimately filled the seat and might have won the race had his seatbelts not come undone to force an unscheduled pit stop.
''I think everything that's happened in my life has happened for a reason,'' Stewart said. ''I think there's things that I would like to have skipped in my life, and things that have not happened, but I think everything in the big picture has happened for a reason.''
Still, he admitted to wondering sometimes if he should have taken Penske's Indy 500 offer, or an offer from Rick Hendrick to move to the Cup Series in 1997 or an offer to drive for Team Kool Green in the CART series.
''I think it's all worked out pretty good since then, so I think we've made the right decisions,'' he said. ''We've always trusted our gut instinct, and I don't think it's led us wrong yet.''