O'Driscoll was so good he could lose 10 per cent effectiveness and still merit a place in test rugby. In all probability, he could have pushed on to 2015 but, as he said, he had to learn to listen to his body. It told him Ireland needed someone else.
Smith is facing a similar situation. Like O'Driscoll, Smith has ticked most career boxes. The one with which he'd like to sign off is being part of the first team to retain the World Cup.
That's the carrot - and he's contracted until the end of next year - but he's not the sort who will blindly commit. He turns 33 this year and, if he has any doubts about his ability to perform at his peak, he'll pull the pin.
Smith's popularity and standing in the game have much to do with his conviction that team is everything. He'd rather be back home watching an All Black victory in 2015 than be in England as part of a losing campaign. He's also single-minded and decisive, having already shown a willingness to listen to his body. He took a short sabbatical at the end of last year primarily because he felt that if he didn't, he'd not be able to maintain his usual consistently excellent standards throughout 2014 and beyond.
There were signs in 2012 and 2013 that his form was susceptible to the odd fluctuation deeper in the season. In 2012, he had poor games against Australia in Brisbane and England at Twickenham. In both tests, Smith's channel was unusually porous; he was a fraction off with his timing, half a metre short of where he needed to be, and attackers were able to escape.
As Smith alluded to in 2012 and 2013, he was being pushed close to his limits by the length and intensity of the season.
"Playing every game of Super Rugby didn't help," he said the week before the loss to England when asked about whether the season was too long and brutal. "All players struggle through the year - I don't think you see a player that plays his best all through the 10 months [of the season]."
No one should believe Smith can't or won't make it to the World Cup but nor can there be any certainty, which presents the All Blacks with challenges this year. How much time should they invest in an insurance policy against Smith not making it to England?
Ben Smith was groomed as a successor on the end of year tour, an exercise that was neither a success nor a failure but a confirmation that he'd need to spend more time in the role to be considered a genuine, like-for-like replacement.
More time, though, is the hard part. Smith looks unlikely to see any action at centre for the Highlanders and, without that, he'd be again learning from his mistakes while on All Black duty - far from ideal. Smith is an option of sorts should his namesake not make it but options of sorts tend to be exposed as inadequate at World Cups.
The All Blacks have had experience of rushing an outside back into centre the year of a World Cup and, while Smith has some experience in the role, he wouldn't necessarily assuage a nation's fears they were about to see history repeat. A more convincing insurance is provided by the impending return of Sonny Bill Williams in 2015.
Who would bet against this: that by the end of next year's Super Rugby competition, the two best and most destructive midfielders in the country will be Williams and Ma'a Nonu? Both prefer 12 but the latter began his career and spent several years at centre before shifting permanently in 2007. Could he head back there?
Could, by the next World Cup, he and Williams be the best All Blacks midfield combination? Williams and Robbie Fruean, for a brief period with the Crusaders in 2011, showed how devastating two big men can be in tandem. Williams getting those giant arms free in the tackle and offloading to a rampaging Nonu ... it's not without attraction.
