Verizon's wireless network is reliable and CTO Kyle Malady intends to keep it that way by enlarging capacity for unexpected changes. The chart at left shows he has more than doubled "capacity margin" despite capex being flat to down since 2013.
(Among other things, this means Verizon has the capacity to bring 25 Mbps down, 3 Mbps up to at least two to three million currently unserved school kids. Probably more.)
Chess Grandmaster Aron Nimzowitsch introduced the idea of "overprotection" in his classic My System. Nimzowitch recommended protecting an important pawn or square more than is apparently necessary. Your opponent may surprise you and need the "over" to respond.