Federer might be more aware of that maxim than any other athlete on the planet, and it explains why he's brought a voice that's likely to be very different from Edberg's into the mix. To some, it's a puzzling decision.
True, Federer just completed his best year in a long time, and at age 34 no less. He won six titles, including a Masters 1000, and reached two Grand Slam finals -- both ending in losses to top-ranked Novak Djokovic.
Also true: Edberg, who had never intended to be a coach -- much less a coach of Federer -- had already been on board for a year longer than anticipated. His contribution as an attack-minded player had been absorbed and incorporated into Federer's game, culminating symbolically if not literally in the Sneak Attack by Roger (SABR) strategy. The partnership was wildly successful.
Federer lost to Djokovic in the two biggest matches the men played, and that means Federer was not satisfied. He isn't the kind of guy who's going to say to himself, "Well, that was great, considering I'm 34." He's going to think about what he can do to beat Djokovic the next time they play. Hence, Ljubicic.
"First and foremost, if you don't think you can [improve], you won't," ESPN tennis analyst Brad Gilbert told ESPN.com. The former coach of Andre Agassi and Andy Roddick added, "By the usual standard, Roger had a remarkable year, but what's really amazing is that this is a guy who really thinks he can still get better. He's never satisfied with the status quo, and right now he has to think about what he can do to beat Djokovic in a five-set match. A hire like this is going to make Roger believe he can do that again. He's going to look at things in a fresh way."
In some ways, the Ljubicic hire is a departure from the course Federer had pursued for some years. Although Swiss Davis Cup captain Severin Luthi has been a permanent coaching fixture in Federer's camp, as a mature pro and Grand Slam champion, Federer was also coached by three men known for their passion for attacking tennis. In order: Tony Roche, Paul Annacone and Edberg.
It was always difficult to see the fruits of the trio's coaching labors. Roche, whose own serve-and-volley game back at the dawn of Open tennis was one based on wicked lefty slice, often seemed more father figure than tactician.
Annacone worked hard on trying to get Federer to attack more, but the results didn't really manifest until Edberg joined Team Federer -- presumably bearing a similar message. Federer's aggression took a quantum leap this season, Edberg's second year on board. The results speak for themselves.
What will Ljubicic bring to this table?
It's an interesting and in some ways puzzling question. A 6-foot-4 Croatian who never played a major final but briefly held the No. 3 singles ranking (2006), Ljubicic was known for his atomic serve and powerful forehand. Like Federer, he hits a one-handed backhand. But he employs a longer stroke and hits a heavier ball than the Swiss star.
Federer's Achilles' heel is a backhand that's a bit on the light side and prone to flying wild. Either way, it can be broken down by heavy bombardment.
Ljubicic's movement was perhaps his greatest weakness as a pro, but that's an area in which Federer needs no help. Over the years, Ljubicic developed a reputation as an excellent strategist and tactician. Federer was more aware of that than most of his peers, partly because the men are friends and partly because they are of the same generation. (Ljubicic is just over two years older than Federer.) They once were frequent practice partners.
"These guys know each other," Gilbert said, "but it's hard to imagine that Roger would have hired Ivan unless the coach had already presented a bunch of ideas and opinions to him."
It probably didn't hurt Ljubicic's cause that he's a friend and neighbor of Djokovic's in Monte Carlo and might have some insight on how to slow down the Serb that others don't.
Federer will surely be dangerous next year, for he knows that rust never sleeps. Then again, Djokovic doesn't either -- at least not in the way that is likely to make life at Grand Slam events easier for his rivals, including Roger Federer.