When a Ford Coil Pack goes bad, does it do so all at once or does it show symptoms first?

96 Windstar is not firing, did not run rough, never hesitated, always silky smooth idle & acceleration, good MPG, no smoke, no rotten egg smell… This morning (warm weather) it will not fire.

Read more: When a Ford Coil Pack goes bad, does it do so all at once or does it show symptoms first?