Super rugby
How it has grown: Had roots in the amateur era, but officially started with 12 teams from New Zealand, Australia and South Africa in 1996. Grew to 14 teams in 2006 and added a 15th in 2011. Last year brought the total to 18, adding teams from Argentina and Japan in the process.
NRL
How it has grown: Began as the NSWRL in 1908 and has added various teams along the way, incorporating clubs from around Australia and New Zealand. Reached saturation point during the Super League War of the 1990s, which eventually resulted in the NRL being formed.
Result: Helped grow the game outside of New South Wales and remains a highly competitive and popular competition. However, has since taken its teams back to 16, showing more was not necessarily better. That came at the expense of several clubs but ultimately made for a better competition.
NBA
How it has grown: Had its biggest expansions in 1976 and the late 1980s, while adding other teams at various times. Moved into Canada with two teams in 1995, one of which survived. Has 30 teams and has been around that number for the past 20 years.
Result: The NBA has grown in popularity and teams to have entered since 1976 have been successful, accounting for nine championships. Its quality remains high and while there are weak teams, it tends to be cyclical as to which teams are struggling.
IPL
How it has grown: Started with eight teams in 2008 and expanded to 10 teams in 2011. Dropped back to nine a year later and returned to eight in 2014. Has seen various teams come and go and at present has two teams suspended due to a match-fixing scandal.
Result: Its money attracts many of the game’s top players and it retains a huge following, particularly in India. Adding and losing teams does not seem to have had a huge impact.
ANZ Championship
How it has grown: Began in 2008, when the New Zealand and Australia netball leagues combined. Lasted until 2016, when Australia pulled out and the countries began their own new competitions. New Zealand will have a six-team competition in 2017, while Australia will have an eight-team one.
Result: The expansion to a transtasman league ended up a failure, although that was more due to the Australia teams’ dominance than the added numbers. Even in hindsight, though, it is hard to criticise the move to combine with Australia, as it had potential and had worked in Super rugby.
English Premier League
How it has grown: Began in its current format in 1992 with 22 teams, but dropped to 20 in 1995. Retains divisions below so teams can break into the top-tier league.
Result: It remains a great competition, despite being a bit top-heavy. The lower teams are still capable of taking points from the top teams and the race to avoid relegation creates interest at the bottom end of the table. Simplistic format too, with whoever finishes on top of the table winning. Shows that you do not have to fix an already good product for it to remain relevant.
NPC rugby
How it has grown: Has tinkered with its format over the years but, notably, expanded its top division to 14 teams in 2006. That killed off the three-division format that had proved successful. In 2011 it created two tiers in the top division, the Premiership and Championship.
Result: Has seen more teams playing at a higher level, but created a flawed format in which no team plays the same 10 opponents. That leaves things unbalanced and getting a favourable draw is more advantageous that it should be. The quality has been diluted, although there are several reasons for that and it probably would have happened regardless of expansion. At the Heartland level it has taken a hit; the second division is no longer the tough competition it once was.
NFL
How it has grown: Has 32 teams and has hovered around that number for the past four decades. Last added a team in 2002 with the Houston Texans joining. Has looked at growing its market outside the United States, although that has come in taking games between already existing teams overseas.
Result: The most popular sport in the United States is becoming more popular around the world. Being the sport’s only major league, it can get away with having a large number of teams, as it attracts all the best talent. Its conference format makes for a short season, meaning it is not overdone and fans are always left wanting more.