Before the 2016 season, Rosberg stopped reading the news and studied sleep with a jet-lag doctor as he focused on his family and winning the next event. He altered his racing gloves to improve his starts, removed paint from his helmet to make it 80 g (2.8 oz) lighter, employed a mental trainer to increase his aggression, and spent his spare time go-karting to maintain his ability. Rosberg eschewed Facebook for five months, studied philosophy, meditated to stay concentrated, and received detailed technical input from Mercedes's mechanics at its headquarters in Brackley, England. He worked with his sports psychologist for up to eight hours per week with two hours of mental discipline every two days. Rosberg said he was confident of driving a competitive car and wanted to maintain his form by beating Hamilton more regularly.
Rosberg, who had signed a two-year contract extension with Mercedes to 2018 in mid-2016, began to contemplate retirement from motor racing when he considered the possibility of a championship win after the 2016 Japanese Grand Prix. He discussed it twice with his wife Vivian before the Abu Dhabi Grand Prix and decided to commit to retiring before the race commenced. Afterwards, Rosberg told Vivian and manager Georg Noite that he would retire before telephoning the Mercedes team principal Toto Wolff about it. He did not tell Wolff in person because he was apprehensive about Wolff's reaction. At a FIA Prize Giving Ceremony in Vienna on 2 December 2016, five days after winning the championship, he made public his decision to retire. Rosberg said he had reached the "pinnacle" of his career; he did not want his driving skills to atrophy and wished to spend more time with his young family. He was the first reigning champion to retire from Formula One since Alain Prost in 1993. Williams driver Valtteri Bottas replaced Rosberg at Mercedes.
Creative Artists Agency (CAA), through its sports division CAA Sports, represents Rosberg's commercial ventures. From 2010 to 2015, he was associated with the jewellery and watch brand Thomas Sabo, and the luxury travel accessory maker Tumi. Rosberg signed numerous endorsement contracts; some of the companies with which he has done business are the watchmakers Rolex, International Watch Company and Oris, the luxury fashion house Hugo Boss, the toy car company Hot Wheels, the railway company Deutsche Bahn, and the media broadcasters Sky Sports and RTL. As a result of Rosberg's endorsement money and Mercedes salary, he was listed as one of the world's highest-paid athletes by Forbes in 2016.