Jose Mourinho believes Arsene Wenger was the last of his kind and says he does not think it is possible for another manager to lead a Premier League club for two decades.
Wenger is the most successful manager in Arsenal's history and won 17 trophies during his 22-year tenure before stepping down at the end of the 2017-2018 season.
Mourinho, by contrast, has taken charge of nine clubs during his 19-year managerial career and recently replaced Mauricio Pochettino as head coach of Arsenal's north London rivals Tottenham.
Asked whether long-term managers like Wenger and Sir Alex Ferguson are now a thing of the past, Mourinho said: "Twenty years in a club? I don't think it is possible.
"Modern life, new technology, social media - I think everything has an influence.
"Even people's mentality, faster relations, getting tired more easily, so many things that are changing. Not just football, but changing the world and the perception of things.
"I think Wenger was the last one."
'We have to fight for our job every day'
Mourinho believes the level of scrutiny managers face in the modern-day game means Premier League bosses are now constantly under pressure to deliver.
"We have to adapt and we have to try to prove we are the man for the job. We have to fight for our job every day," he said.
"I think that the times when people know the job is going to be mine for X years [are over] - you have to fight every day, not just with football results but everything you do in the club and I think it is normal.
"It happens in society and in so many areas - I can imagine yourself, even in your newspaper and your radio, you have not just to sleep on what you did previously, you have to show every day you are the guy for the job."
Asked if managers now have a time limit for success, Mourinho said: "I don't think about that. I think about trying to show I am the man for the job every day."