The 71-year-old confirmed on Wednesday that the 2012-13 season is to be his last but the veteran midfielder is, however, optimistic that "everything is in place" for his successor to do well. As revealed by Goal.com, Everton boss David Moyes is on the verge of being unveiled.
"But I think usually when a manager leaves a club it's because they are not doing well or they are in a transitional stage. So when the manager leaves – you've got great fans, great players and you've got a great stadium – everything is in place for the next person to take it on to the next level.
"Whether the next person can do that remains to be seen as nothing is guaranteed but Sir Alex will be tougher to replace than the players."
Giggs also reminisced over his first encounter with Sir Alex while playing for Manchester City in his early teenage years and how he eventually came to turn out in a Red Devils shirt.
"I was at Man City from 11 years of age. There was a local team that I played for and the manager was a Man City scout," he recalled, "but I had always been a United fan. My local team that I played for, Salford Boys, Sir Alex Ferguson used to come regularly and watch and Brian Kidd, who was the youth development officer at the time, also used to come and watch.
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"It was obviously strange having the manager of Manchester Utd sitting in my front room, speaking to my parents, and personally coming to ask you to sign for Manchester United. It was on my 14th birthday and, of course, I had no hesitation in saying yes."
The Welshman also heaped praise on Sir Alex for keeping him grounded and away from the usual pitfalls that can tarnish many a young prospect's career.
"He kept my feet on the ground and when things were even going right he kept a level head," Giggs added. "When you have a bad game or even a good game he doesn't overreact too strongly with too much praise or too much criticism.
"It was important to keep balanced especially as such a young player coming into the team. At 17, 18, 19, you can get big-headed and think that you've made it already but of course you haven't."