Experience can be an unrivalled thing to have at a World Cup when you get to the pressurised environment of the latter stages.
It can be even more important if a shock group-stage exit is on the cards and you need someone to pull the rabbit out of the hat and rescue the team.
No manager wants to go into a major tournament without at least a handful of experienced stars who have been there and done that before.
What is the oldest squad at the World Cup?
We're going to use the median age as there are multiple different measurements that throw up different results for the oldest squad. The median age of both the Belgium and Iran squads is 29. To pick one, we're using the fact that 11 of the 26 players in the former's squad have 50 caps or more, and six of them are into triple figures which is more than any other squad at the Qatar World Cup.
Much has been made of the fact that this could be the last chance for Belgium's golden generation to win a major tournament after promising so much over the last ten years or so. The fact they are the oldest and most experienced squad in Qatar shows that Roberto Martinez is still relying on the old guard with just a few youngsters scattered into the squad.
There are five players in the squad who are 22 or under: Zeno Debast (19), Jeremy Doku (20), Charles De Ketelaere (21), Amadou Onana (21) and Lois Openda (22).
Beyond them, the likes of Simon Mignolet, Thibaut Courtois, Koen Casteels, Jan Vertonghen, Toby Alderweireld, Axel Witsel, Thomas Meunier, Kevin De Bruyne, Hans Vanaken, Dries Mertens and Eden Hazard are all in their thirties.
Belgium are in Group F where they will be battling Canada, Croatia and Morocco, which means that they have a good chance of getting to the Round of 16. That is where the real hard work will start though if this crop of stars are going to finally win the World Cup.
Who is the oldest player in the Belgium squad?
There are two 35-year-old players in the Belgium squad, but it is Jan Vertonghen who takes the crown as the oldest on the plane. He is a couple of weeks older than forward Dries Mertens.
It feels like Vertonghen has been around forever now, which is likely because he has. He kicked things off at Ajax back in 2006 where he made 155 appearances. He then spent eight years at Tottenham Hotspur where he made over 230 appearances before a spell at Benfica. He has now returned to his home country with Anderlecht.
He has played 141 times for the Belgian national team since making his debut back in 2007 and has played at the 2014 and 2018 World Cups.
Who is the oldest player in a World Cup squad?
The record for the oldest player to feature at a World Cup was actually broken very recently. At the 2018 tournament in Russia, Essam El Hadary played in goal for Egypt at the age of 45 years and 161 days.
It is often goalkeepers that break the age records, but Cameroonian legend Roger Milla is still third on the list having played at the 1994 World Cup aged 42 years and 39 days.