The saying "nothing lasts forever" is particular apt when applied to the career of a professional footballer, and even more so when relating to a player's time at the top of the game.
Luis Figo, Michael Owen, Ronaldo, Pavel Nedved, Andriy Shevchenko and Fabio Cannavaro have all dipped out of not just the top level, but the game itself.
And, despite the longevity of players like Ryan Giggs and Javier Zanetti, there still remains an expectation that players careers will begin to falter as they head into their 30s.
With that in mind, is it possible for Cristiano Ronaldo to continue to hit the unbelievable heights he has consistently reached for Real Madrid in recent seasons?
Over the last three campaigns, the Portuguese forward has managed 168 goals in 164 games for Los Blancos, leading to Sir Alex Ferguson telling The Independent in February that he is "at the peak of his career."
The 28-year-old, who is less than two years from 30, told TVI (via Goal.com) that he disputes the train of thought that suggests he's at his best:
I just hope I will keep seizing the moment year after year. I have not yet reached the peak of my career. This is all just relative. Next year, I could be at a higher mental level and not score as many goals.
Ronaldo's major concerns lie around the style of his game. A large part of his reputation, particularly since his early days with Manchester United, has been built on pace and his ability to beat a man.
A player's speed is an aspect that is known to deteriorate with age, although Ronaldo is unlikely to see a significant decrease in his athleticism over one summer, which consists of barely more than two months away from competitive football.
Last season he scored 34 goals in 30 La Liga starts—plus a further four substitute appearances—and 12 in 12 in the Champions League.
On top of that, there is the continued interest from Manchester United, as reported by Matthew Morlidge of the Daily Mail. And according to The Independent's Jack Pitt-Brooke, Monaco are prepared to offer the Portuguese attacker big bucks to bring him to France—this also doesn't lead naturally to the conclusion that Ronaldo has hit his ceiling at Real Madrid.
And as a man who looks after himself and his physique so well, that's the correct conclusion.
It's true that one day Ronaldo may have to re-evaluate his style of play—his pace and explosiveness won't last forever—perhaps using players like Ryan Giggs as an example of ways in which you can adapt your game as you get older.
Although that day isn't coming any time soon for the former Sporting Lisbon winger, and he has, at the very least, three to four years remaining at the very top of world football.
Sir Alex Ferguson is probably right, Ronaldo is in the peak of his career right now. For Ronaldo to say otherwise is peculiar; just because he is at his peak now, it doesn't mean it can't continue for several more years.
Providing he stays at the Bernabeu, Real Madrid fans can expect plenty more goals and match-winning performances from their No. 7 next season; he's not heading the way of Cannavaro, Owen et al any time soon.