Most players actually peak in strength around age 35 [1]. But Carlsen has been number one for more time than any player for him, safe Kasparov [2]: - Kasparov

Most players actually peak in strength around age 35 [1]. But Carlsen has been number one for more time than any player for him, safe Kasparov [2]: - Kasparov 255 months at number 1 - Carlsen 188 - Karpov 102 - Fischer 54 Bonus nuance: Carlsen has the longest unbroken run of 174 consecutive rating lists [1]: https://en.chessbase.com/post/the-age-related-decline-in-chess#:~:text=Figure%201.%20Asymmetric%20cubic%20curves https://en.chessbase.com/post/the-age-related-decline-in-che... [2]: https://en.wikipedia.org/wiki/List_of_FIDE_chess_world_number_ones#:~:text=since%20July%202011.-,Time%20at%20FIDE%20number%20one%20and%20youngest%20age%20at%20FIDE%20number%20one,-Player https://en.wikipedia.org/wiki/List_of_FIDE_chess_world_numbe...