The identity of a football club is a fragile thing.
It can change with each new owner and with every new manager. It's rather less seismic, but it changes with each new player who arrives and every one who leaves.
It's more than the four stands of the stadium or the pitches at the training ground.
It's a living, breathing organism. Constantly changing. Forever evolving.
Every club has its core values. Its own history. The most successful clubs have made their players aware of it. Of what it means to wear that particular shirt. Of what they are representing.
Manchester United, especially under Sir Alex Ferguson, have always been keen to retain the services of those players who understand it best.
Sir Bobby Charlton has been a director since 1984. Brian Kidd, who won the European Cup alongside Charlton and George Best in 1968, was Ferguson's assistant between 1991 and 1998.
Former Busby Babe Jim Ryan spent years in charge of the academy. Brian McClair took on a coaching role at Old Trafford almost as soon as his playing career finished in 1998. He's now the academy director.
Nicky Butt has been coaching the Under-19s, with the help of Paul Scholes. David Moyes brought Phil Neville with him from Everton to be part of his backroom staff.
Moyes also offered Ryan Giggs a coaching role last summer. It is one he's combined with his playing duties this season.
This campaign might yet be Giggs' last as a player. At 40 years old, he's earned the right to choose how and when he hangs up his boots.
But for Moyes to let Giggs end his association with United altogether in the summer would be a mistake.
Giggs knows better than most what the club is all about. And that's a valuable commodity as United head into a new era.
It is understandable that Moyes might feel vulnerable with Giggs on his coaching staff.
At the press conference ahead of the Champions League quarter-final first leg with Bayern Munich, Giggs and Moyes sat next to each other as one inquisitor asked whether the Welshman was a future United manager.
Giggs laughed it off while Moyes turned to the press officer on the top table to step in. She did and the question went unanswered. It was a sign that Moyes is still not entirely comfortable in his new job.
But letting Giggs walk out of the door in the summer isn't the answer. It will only create more distance with the fans in the way the departures of Mike Phelan, Eric Steele and Rene Meulensteen did in the summer.
Giggs is one of the personalities who has helped define United. He's grown up there and become a symbol of their success over the last 20 years.
Simply put, he has something you can't replace. And United will lose a part of their history, a part of their appeal, if he's allowed to leave at the end of the season.