Man Utd boss Sir Alex Ferguson has praised Everton for giving David Moyes enough time to shine at Goodison Park.
Moyes is among the longest-serving league managers after being appointed by the Toffees back in 2002.
The former Preston boss has transformed Everton in that time, including finishing fourth in 2005.
But he has also had to endure prolonged relegation battles in 2004 and 2006 and Ferguson feels the Everton board were right to stick with their man during the tough times.
His comments come as United travel to Goodison Park for a crucial match on Saturday lunchtime, with the Red Devils hoping to maintain their push up the table.
Ferguson said: "I have said time and time again, there is no evidence changing a manager brings you success.
"Time helps to get success. You cannot go against the experience of being at a club for a long time.
"If directors have knee-jerk reactions to bad results and go back on the faith in their manager and the very reason they appointed him there in the first place, they will never get that consistency and continuity in management style.
"David spent a couple of years building a football club at Everton. It is what he had to do. But you can't do it if the time is taken away."
He added: "What David did very well was to get a group of young players in the team and then give them all longer contracts.
"He got them all tied down for a good number of years, which meant it was not just the continuity of the manager but the continuity of the playing staff as well, which gives you a better chance."
Everton have three former United men in their ranks - Tim Howard, Phil Neville and Louis Saha.
The France international ended four injury-hit years at Old Trafford on transfer deadline day when he moved to Merseyside on a two-year deal.
Ferguson hopes the player can return to the sort of form which persuaded him to sign the striker from Fulham for £12.8million.
The United boss added: "Louis just didn't give us enough football.
"We have had experience in the past that some players leave here, then continue their career quite well despite having suffered a lot of injuries with us.
"Hopefully Louis does that for Everton. What happened here was frustrating for all of us because we know the ability he has got."