Players look to create them, avoid them, and score from them, the latter often turning the tide in an otherwise close contest.
For Notre Dame's football team in 2011, they were referred to as something else:
Turnovers. 29 of them – or for the sake of reference, more than 109 of 120 FBS schools – waylaid what could have been a double-digit win season in head coach Brian Kelly's second at the helm. The veteran play-caller and program architect knows his 2012 team can't again treat possession of the pigskin in such a careless manner.
"We clearly believe that we've got enough plays, that we've got enough answers," Kelly began of his offense heading into the spring. "Growing and evolving for us will clearly be about taking care of the football from an offensive standpoint. We believe we have the ability to run it and throw it. It (losing) was clearly centered around the negative plays on the offensive side of the ball. I don't think anybody, when they saw our offense running effectively, looked at it and go, ‘Wow, this is an offense that needs more work.'
"It is certainly an offense that can be effective at the BCS level and help us win a championship. It can't be, from what we saw in terms of turning the ball over."
Remove the comedy of errors that was the season's opening contest (five turnovers) and the unplanned encore in a Week Two loss at Michigan (five more), and Notre Dame's offense still wouldn't have finished among the top 40 nationally in terms of protecting the football.
Three turnovers contributed to losses vs. USC, Stanford, and Florida State as well (six interceptions/three fumbles). Notre Dame committed 19 turnovers in five losses but more troubling was the reality that the Irish offense lost possession 10 times in its eight wins, or exactly the same number of turnovers committed all season by BCS powers LSU and Wisconsin (with an extra game for both, to boot).
Only three times did Kelly's Irish offense play turnover-free football in 2011: Purdue in Game 5; Air Force in Game 6; Maryland in Game 11.
Continuing his three-year trend?Notre Dame lost five games in 2010, committing 3, 3, 2, 2, and 4 turnovers in defeats at the hands of Michigan, Michigan State, Stanford, Navy, and Tulsa, respectively. The Irish offense likewise lost the ball 10 times in their eight 2010 victories (including four miscues in a win at USC).
That's 20 turnovers in 16 wins; 33 in 10 defeats of the Kelly era.
Consider first that Kelly's 2009 Cincinnati squad coughed up the rock just 10 times (lowest in the nation) in his 12 games as Bearcats head coach that fall.
But then consider the following: Kelly's second season in Cincinnati yielded 30 turnovers (14) games, or one more than his Notre Dame committed last season (13 contests). His first season coaching the Bearcats featured 26 turnovers, two more than his first Irish squad committed in the same number of outings.
56 turnovers in his first 28 games in the Queen City; just 10 in his final 12.
Notre Dame's inconsistent offense suffered 53 turnovers in Kelly's first 26 games as Irish head coach. But can Notre Dame fans expect a similar turnaround for Year 3 in South Bend?
It seems inconceivable entering the spring, but if the Irish continue to move the ball, and finally protect it, the BCS likely awaits.