Tadhg Furlong was a rookie prop at the last World Cup, not only a blossoming tighthead but also covering the loosehead side of the front row.
So he knows exactly what fellow Ireland tightheads Andrew Porter and John Ryan are going through as they reacquaint themselves on the other corner in their bids to make the 2019 squad for next month’s tournament in Japan.
With World Cup rules capping squads at 31 players, even players in specialist positions have to showcase their adaptability as coaches look to give themselves as many options as possible in the event of losses through injury or suspension.
Ireland boss Joe Schmidt is no exception to the rule and had tighthead Porter covering at loosehead for much of the second half of the opening summer Test against Italy on August 10.
Both Porter and Ryan started out on that side of the scrum before switching to tighthead but Furlong was a dyed-in-the-wool number three, albeit yet to be capped by Ireland, when he was asked to fulfil the auxiliary role in England and Wales four years ago.
Four years on, Furlong is his country’s undisputed first-choice, regarded as one of the best tightheads in the game and with three Tests for the British & Irish Lions among his honours.
Speaking in Portugal, where Ireland are preparing at a warm-weather training camp on the Algarve for Saturday’s Test against England at Twickenham, Furlong looked forward to his first game of the summer campaign and back on how his circumstances have changed from the last World Cup.
“I was trying to force myself into contention in 2015,” Furlong recalled. “Looking back on this stage four years ago, I didn't have a cap.
"I got my first cap in the second-last warm-up against Wales. Four years on, you hope you're a little bit wiser and a bit more self-assured on where you are and what you can contribute to the team.
“Pre-season has been tough and enjoyable and challenging but you love playing rugby and it's what you've done since you were a kid, so everyone is raring to go.
As for who is now looking to provide cover at loosehead, Furlong said his Leinster team-mate Porter was a safe pair of hands for the role and being well looked after by the specialists in the training group, Cian Healy, Jack McGrath and Dave Kilcoyne.
Furlong said: “He has a lot more experience at loosehead than what I did. It was my second cap when I came on at loosehead against England.
"He knows what he's doing a bit more at loosehead than I do. I probably leave that to Church, Jack and Killer giving him tutorials.
“It's the second pre-season game and a few of the lads are going to be having their first run-out of the season. You have to make that distinction that we're not here as just a hard training week and we're going home at the weekend.
"We have a big game this weekend and everyone is excited. It's tough work that we're doing but hopefully there's an end result to it.”