The 33-year-old was named as new Chelsea manager in June.
Buck told BBC Sport: “We do envy Arsene Wenger at Arsenal and Sir Alex Ferguson at Manchester United in terms of longevity, but it shouldn’t be longevity for longevity’s sake.
“It has to be the right guy in the job for 10 or 15 years and, in light of Andre’s age, he may well be that guy.”
Buck added: “Everyone thinks his age might have been a negative but it’s a positive.”
Chelsea have lost only once in Villas-Boas’ 10 games in charge of the club.
Buck said: “He has really been able to relate to the players. He is a very organised guy who really understands football.”
