There are a few different abilities that PCs can get where once they are hit with an attack they can decide to use to potentially turn the hit into a miss. Examples include the spell Shield or a Cavalier fighter's Warding Maneuver feature.
The way our group currently plays all the DM's rolls are hidden from us and they convey whether attacks hits or misses to us. In the case of a hit the player informally has until the DM rolls damage to decide whether to use a feature that might change the outcome.
While the players are aware of when an attack is a hit, are they aware if the attack is a critical hit? If so they would know that using such features would be a waste of resources.
This would also apply to rare features that can force a reroll after an attack roll is already made such as with the Rune Knight's Runic Shield feature. If a player knows that an attack is a critical hit they would be more inclined to use such features.