Match the recipe job: for French toast/stuffing, choose a substitute with the most moisture-retaining softness (brioche or egg bread first).
Use the listed swap ratio; if your substitute is sweeter (like Hawaiian sweet bread), start at ¾ of the amount.
For bland bread (like white sandwich bread), mimic challah’s richness by soaking slices briefly in an egg-milk mixture before using.
If the substitute is very soft (milk bread, Hawaiian bread), shorten soaking time to prevent mushiness.
Taste the final result: add a pinch of salt or reduce added sugar in the recipe if the substitute is sweeter than challah.