First there came those hallowed figures who were already established by the time I took interest in the late 1990s. Next came those who I grew up with in the 2000s, before a new era of names gradually rose to the fore to dominate the podium positions of today.
While virtually all of the first group of names - Pete Sampras, Sir Steve Redgrave, Ian Thorpe, Michael Schumacher and Lance Armstrong - have long gone in a competitive sense even if they still make headlines in other ways, many of the second group have now moved on too.
Some have retired - Sir Chris Hoy, David Beckham and, at least for the time being, Michael Phelps - others have called time on international or Olympic duty - Thierry Henry, Jonny Wilkinson and Sir Ben Ainslie - while others like Asafa Powell have departed in disgrace.
Roger Federer and Kenenisa Bekele are two who are still around but, after a steady decline for each in recent years, they have now reached a crossroads where their careers will either peter out or be revitalised again for a glorious Indian summer in 2014.
If I was compiling a list of my all time favourite sports stars, and I am sad enough to occasionally do this, both men both would be very close if not at the top. Few others have provided the range of glorious highlights over the last decade in the way each done in a cascade of ferocious forehand winners and scintillating sprint finishes.
Federer burst on to my radar in 2001 with his ousting of defending champion Sampras at Wimbledon - I was on the way to a primary school "nature quiz" competition if I recall correctly - although it was in 2003 he won his maiden SW19 title.
For the next four years he was virtually invincible as he won 11 out of 12 non-clay Grand Slams as the likes of Andy Roddick, Leyton Hewitt and Tim Henman were good enough only to bring a drop of sweat to the ice cool Swiss brow.
A credible opponent did gradually appear in the form of the hulking Majorcan matador Rafael Nadal, who beat Federer in three successive French Open finals even if he had markedly less success elsewhere.
Even when Nadal finally got the better of him on grass he lost magnificently. As for many of my generation the Wimbledon final of 2008 was an event I feel privileged to have witnessed. Regarded as perhaps the greatest match of all time, Nadal was two sets up and simply too good before Federer fought back to take two tie breaks in a fashion which simply defied belief.
There was one match point, for example, where Nadal hit a strong first serve followed by a thunderous forehand approach only for Federer to rifle a backhand through the eye of a needle for a winner that was as gutsy as it was magnificent.
Nadal showed his own greatness by holding his nerve to win the deciding fifth set but if you are going to lose that is the way to do it. Four hours and 48 minutes of sheer sporting brilliance.
In recent years Federer has never dominated to the same degree and has had two other members of the "fab four" in Novak Djokovic and Andy Murray to contend with, as well as Nadal.
He has still won at various points however, to take his total Grand Slam tally to 17, and he has combined this perseverance with a scarcely believable ability to avoid injury.
But after a steady, barely noticeable decline, in 2013 this became a slump. No Grand Slams and, for the first time, dispatched well before the latter stages in several of them. He even seemed somehow less likable - his charm suddenly transcended to arrogance in the face of his three younger and even more gracious rivals.
Here his dominance was so great that he was able to deliberately slow the pace down to allow Haile Gebrselassie to catch up and thus ensure, not just victory, but an Ethiopian clean sweep.
Although he was defeated over 5,000m at those Championships, as well as at the Athens Olympics the following year, where Hichm El Guerrouj got the better of him in the ultimate miler versus distance runner showdown, Bekele would go on an eight year unbeaten run at the longest track event in a streak that included four world and two Olympic titles.
Like Federer, 2004 and 2005 were his years of absolute dominance where he was breaking world records for fun as well as winning titles but, like Federer, he also continued to win even when those best years were behind him, and took the rarest of 5,000m and 10,000m doubles at Beijing 2008.
Like Federer, Bekele also turned to a fellow athlete for love. But while Federer eventually married Mirka Vavrinec, who he met when both were competing for Switzerland at the Sydney Olympics, Bekele's fiancé Alem Techale tragically collapsed and died in 2005 while the pair were together on a training run. Despite the grief he won the World Cross Championships just two months later and married film actress Danawit Gebregziabher in 2007.
At the 2007 Cross Country Championships in Mombasa, the searing Kenyan humidity forced Bekele to pull out and handed victory instead to a great rival, Eritrea's Zersenay Tadese. But the Ethiopian got the better of the Eritrean at the 2008 event in Edinburgh. Then at the 2009 World Championships in Berlin over 10,000m, Tadese's relentless pace in the latter half of the race was too much for everyone. Everyone that is, except Bekele, who hung on to him before kicking away with a sense of divine inevitability over the final lap.
It was those Championships in Berlin which also provided my favourite Bekele moment when he out-sprinted Kenyan turned United States rival Bernard Lagat in the home straight of an otherwise pedestrian 5,000m race which he simply had no right to win over the second fastest 1500m runner in history
Since then Bekele has struggled with injuries which have robbed him of both his consistency and finishing pace. But while Britain's Mo Farah has taken over the summit of the sport, he has yet to get anywhere near Bekele's best times and I would suggest that if both were at their best there would be Ethiopian rather than "Mobot" celebrations at the finish line.
When that clash of sorts did occur, albeit on the road, at last year's Great North Run, Bekele produced a tactical master-class to break clear and hold on for a brilliant victory.
I was at the World Triathlon Series Final in Hyde Park at the time and, in the press tent at least, no one was watching the triathlon but were engrossed by the small television screen showing these two great titans going head to head.
The New Year is a new start for both Bekele and Federer.
Bekele announced last week he will continue his transition to the road by taking on the Paris Marathon in April. In a competitive sense he hardly set the world on fire at the weekend with fifth place at the BUPA Great Edinburgh Cross Country, but with 200 kilometres per week of marathon training in his legs you cannot read too much into a result over a distance as short as four kilometres.
"Of course, if I train hard I will do a fast time", he said regarding the marathon this week. "The only thing is I have to prepare myself and train hard until I finish a marathon. I have to motivate myself to train hard to be ready to put myself in a good position. We will see in the end what the result will be."
Quiet confidence if ever I heard it.
Federer meanwhile has appointed a new co-coach in Sweden's former champion Stefan Edberg for the 2014 season. With his rivals as strong as ever the challenge for him appears harder still, but whenever he still has that drive and determination you would write him off at your peril.
His first test comes this week at the Australian Open in sweltering Melbourne. "Of course, we do believe we can knock them off, yes," he replied when asked if he felt he could get the better of the likes of Nadal and Djokovic once again.
Confidence from him as well then.
So while sport has moved on since the halcyon days of the mid 2000s and a new generation has appeared there are two throwbacks who have as of yet refused to go away.
For each 2014 could bring despair, failure and even retirement. But it could, just perhaps, bring success in the shape of a marathon world record and an 18th Grand Slam.