Before 2008 the coin toss winner got to choose between receiving the ball or deciding which end of the field to defend. The other team got the same option for the second half. Most teams obviously chose to receive the ball because why would you not? In 2008 the NFL added the option to defer - the winner got to make their choice in the second half and the loser got the first half.
MMQB has an article on the change. It started slowly (as all things do in life). The first coach to almost always defer was Bill Belichick. In 2011 and 2012 people started noticing and numbers jumped. By now it’s pretty much the default option for every coach in the league.
Before 2008 the coin toss winner got to choose between receiving the ball or deciding which end of the field to defend. The other team got the same option for the second half. Most teams obviously chose to receive the ball because why would you not? In 2008 the NFL added the option to defer - the winner got to make their choice in the second half and the loser got the first half.
MMQB has an article on the change. It started slowly (as all things do in life). The first coach to almost always defer was Bill Belichick. In 2011 and 2012 people started noticing and numbers jumped. By now it’s pretty much the default option for every coach in the league.