It's a good question, and one that current assistant manager Mike Phelan is uniquely positioned to answer.
The 58-year-old was a player at Old Trafford under Sir Alex Ferguson from 1989 to 1994, as we embarked on an extraordinary period of success, before returning to the club at the beginning of the following decade as a coach.
Phelan was at Sir Alex's side as the Reds re-established ourselves at the top of the Premier League tree, and then the European game, and, after leaving when the great man retired, is now back at United as Ole Gunnar Solskjaer sets about his current project.