Major Differences Between This Year's Manchester United and Last Year's

If you've been living in a hole in the ground for six months, you might not know what changes there have been at Manchester United.

It's your only excuse.

Sir Alex Ferguson's retirement made the back pages all over the world. David Gill's decision to step down as chief executive was more low-key, but still significant.

The handover from Ferguson and Gill to David Moyes and Ed Woodward is a monumental shift. 

Between the old guard they had 36 years experience in the day-to-day running of one of the biggest football clubs in the world. Moyes and Woodward have none.

They're learning in their roles—as well as developing their own relationship—but it's only normal for that process to take time.

Of the squad that won the Premier League title by 11 points last season, Paul Scholes has retired for good and Marouane Fellaini and Wilfried Zaha have come in. Fabio has returned from his season on loan at QPR, while Adnan Januzaj has announced himself as an established member of the first team.

That should mean the squad is stronger. But that hasn't been reflected in the results so far this season.

Key players like Michael Carrick, Nemanja Vidic, Rio Ferdinand and Patrice Evra—all over 30—are a year older. But David de Gea, Rafael, Jonny Evans, Tom Cleverley and Danny Welbeck are more experienced.

Wayne Rooney is enjoying a far better season than last year, but Robin van Persie has been hampered by niggling injuries.

Moyes isn't the only new face on the coaching staff. His first act as United manager was to dispose of Ferguson's trusted lieutenants, Mike Phelan, Rene Meulensteen and Eric Steele. In their place arrived Steve Round, Jimmy Lumsden and Chris Woods.

Phil Neville has also come in to act as the link between players and staff, and Ryan Giggs has been made a player/coach.

It's a huge turnover. One set of ideas and practices has gone out and another has come in. It's only natural that players take time to adapt to that level of change.

On the field, the changes are less obvious.

Ferguson's stock formation for the majority of his 26 years at Old Trafford was 4-4-2, and that's not markedly changed under Moyes, who was a fan of variations of  4-4-1-1 at Everton.

The biggest revolution he has implemented at United is playing with a higher defensive line.

But in going through all the changes—big and small—that have taken place at Old Trafford in the last six months, it's impossible to escape the fact that the man who ran the club from top to bottom for a quarter of a century is now gone.

The X-factor he brought has been called the "Fergie Factor," but it's hard to nail down what that actually means.

His input on the training field was minimal in his later years, but he remained a master motivator to the end. Whether they loved him or hated him, his players always had an unwavering respect for their manager, and that goes a long way, especially when things aren't quite going to plan.

His departure, coupled with a series of disappointing results in the Premier League this season, has led to the aura of invincibility slipping ever so slightly.

It's been just enough for West Brom, Southampton, Sunderland and Stoke—United's whipping boys for nearly two decades—to smell the chance of an upset.

If history has taught us anything it's that every empire eventually crumbles. And it's never more vulnerable than when there's change at the top.

Moyes has said it might take two years for him to put his stamp on his new club, according to the Daily Mail's John Drayton. And he's still in the process of weathering the initial storm.