The crusts aren't a choking hazard once they learn to chew them. Unlike a cracker that dissolves in the mouth the crusts - mainly it is the top crust not the sides and bottom and especially if toasted. For kids over 18 months would not consider it an issue at all but for those under that are not adept at chewing it can be. Bread itself unless in small pieces can be more of a hazard to a little one than the crust cause it wads up and becomes a soggy ball of stuff in the mouth. One of the reasons I always toasted the bread for the younger ones cause they just play with bread and squash it. The top crust such as on a grilled cheese I find gives the toddlers issues so I pull it off for awhile.

It used to be that things like apple skin wasn't given to kids under 2-3 lest they chocke but over time some of those rules have gone by the wayside thank goodness.

Mostly think about it yourself if something is going to "go down the wrong way" as they say it is often a big bite that involves a piece breaking off such as the toasted top crust.