For some, just reaching the European Championship is enough. However, from the players to coaches and referees to administrators, many have something to prove in France.
There's a lot riding on Euro 2016 for the tournament organizers. Purists reacted badly to UEFA adding another eight teams to make it a 24-team tournament for the first time. But this tournament has regularly evolved, since only four teams contested the finals until 1980.
A spate of drab first-round games in France could see calls for the expanded tournament format to be reassessed, especially with most third-place teams advancing from the four-team groups to the new round of 16.
But qualifying was more captivating than UEFA's critics predicted, with a format designed to help smaller teams reach the finals still rigorous enough to see the Netherlands, World Cup semifinalists in 2014, miss out.
UEFA could always pin the blame on Michel Platini. Expansion was the brainchild of UEFA's banned, outgoing president who pandered to smaller nations in the now 55-nation confederation.
With Platini out of the picture, one of the first things UEFA did was approve the use of goal-line technology for the first time at one of its tournaments.
Yet, UEFA is persisting with deploying Platini's five officials, with an extra assistant to the referees behind each goal. Since they are no longer relied on to judge if the ball crossed the line, the AARs (as few beyond administrators call these additional assistant referees) will have to prove they still have a role to play in soccer by spotting any misdemeanors in the penalty area.
In the Euro 2016 shop window, eye-catching performances can secure a big-money transfer for players or ensure a pay increase from their clubs.
But for veteran players it's a chance to prove they can cut it at the top level or finally win a title with their national teams.
Take Wayne Rooney and Cristiano Ronaldo, former Manchester United teammates who are already the wrong side of 30. They have already established themselves as the all-time leading scorer for each of their countries. Winners' medals are still missing.
Rooney's last England goals at a European Championship came 12 years ago. He's only managed one goal at a World Cup since then.
While Rooney faces stiff competition to retain his place in England's starting lineup, Ronaldo remains the mainstay of Portugal.
When Ronaldo struggles, so does Portugal. Across 13 games at three World Cups, the Ballon D'Or holder has only scored three goals. After another grueling season with Real Madrid, as was evident in the Champions League final, Ronaldo may struggle to carry his national team.
Tournaments are a series of judgment days for coaches. Many won't survive to lead their countries into World Cup qualifying in September. Some won't be lamented by fans if they do depart.
Take Vladimir Petkovic, who doesn't get the acclaim he feels he deserves in Switzerland.
Petkovic's more popular and illustrious predecessor, Ottmar Hitzfeld, was paid much more and was more in demand with sponsors.
That rankled with the Bosnian-Croat coach who also dislikes regular public debate — including by his own players — about the Swiss-ness and identity of a squad that draws players from diverse family backgrounds, especially the former Yugoslavia.
Leading Switzerland into the quarterfinals of a major competition for the first time since 1954 might change Swiss perceptions about Petkovic.
In the Northern Ireland camp, Michael O'Neill doesn't so much have something to prove but a lot more to be gained from a successful tournament.
Despite previous managerial experience being limited to modest lower-league Brechin City in Scotland and Shamrock Rovers in Ireland, O'Neill was handed the Northern Irish job in 2011. The way O'Neill has modernized the team setup and raised standards has impressed far beyond the country with a population of less than 2 million.
A strong showing in France could see O'Neill in demand for bigger league jobs in football, having already stunned Europe by not just leading Northern Ireland into its first European Championship but as group winners.