If there's one thing we know it's that rugby is a 23 -man game these days. The coaches make sure we're fully aware of it.
If, as now seems likely, Felix Jones dons the No 23 jersey against South Africa on Saturday evening, he will be hoping the oft-repeated phrase rings through. Doubts abound over Rob Kearney's fitness and the in-form Munster full-back is hoping to win his seventh cap in the biggest game of his career.
The balance of Joe Schmidt's bench will be one of the more important decisions for the coach this week and he has always had a reason behind each selection.
The New Zealander and his management team met in their selection room at Carton House last night to finalise their choices and Les Kiss intimated that the make-up of the replacements' list would be high on the agenda.
"We want to continue with having good impact and good service from the bench," the assistant coach said yesterday.
"So we want to be able to make sure that our whole selection matrix works, to get the game done from the beginning to the end. It is a sort of tricky situation, we do have some injuries and that just gives us the opportunity to look at who we've got."
A few minutes previously, Jones had occupied the same chair and fielded questions on his ambitions for the weekend. It would be highly unorthodox for any player to be put through that wringer if he wasn't going to have some involvement.
His international career has been a frustrating experience with the nadir coming on his last appearance in an Ireland shirt at the Aviva Stadium when he suffered the injury that would keep him out of the 2011 World Cup having played his way into Declan Kidney's affections.
"It's probably been stop-start," he conceded of his Ireland career. "That would be a good way of describing it.
"I've had a couple of injuries that have probably curtailed a little bit of my development there, but I keep coming back and keep trying to get myself involved. I'm just looking to put my best foot forward again.
"That (injury against France) would have been the killer blow, of course. But I've moved on from it. It's just a part of it now and you have to adapt.
"You might have to change a few things about yourself. You just have to adapt or die, I suppose.
"Guys that come back from injury, they may be lacking in certain areas or it's always a rush to get back. You always want to get back in as quick as you can and, say it's a foot injury, a shoulder injury, whatever it might be, you might be limited in what you can do so you have to develop in other ways.
"You've got to spend time away from the pitch when you aren't playing, developing other skills, while trying to get the more efficient area back up to par. You just have to adapt, keep developing yourself."
Since that France game, he has won three caps in three years, all coming on summer tours against the United States, Canada and Argentina.
During that time, however, he has earned high praise from Schmidt who clearly rates him. Jones, however, is a victim of timing and has Kearney blocking his path just as he did when he started out in the Leinster academy.
The Louthman appears to be winning his race to be fit to win his 56th cap on Saturday after missing Leinster's last four games but Jones is ready to step in if needed.
"I'd have a very good relationship with Rob," he said. "We talk a good bit, be it after reps, to see what each other is thinking. Look, if Rob was gone I'd be more than happy to step in and likewise if I was gone and Rob were to step in. I'm hoping to be involved, of course.
"It's been a pleasant relationship. He's a sound guy, a nice guy. I'm trying to put my best foot forward in terms of what we're doing out here and if I get an opportunity then great, I'll be looking to put my best foot forward this weekend."
Whether that's from the start or off the bench, Jones says it won't affect his preparation.
"Everyone has to be prepared. You could be in the game after five minutes or you could come in for the last minute and the game could be on the line," he said. "You need to tick all your boxes. You need to know every play inside out for, potentially, a number of positions from the bench because you could be covering two or three."
Ireland are up against it this weekend and there is little doubt that the bench will need to contribute. Whenever he's called into the action, Jones says he is ready to perform against the Springboks.
"South Africa are number two in the world. You want to be testing yourself against the best in the world, so yeah, absolutely," he said.