[foldr]

>but they often use volumes where you'd expect weights (particularly for baking)

Baking recipes in the US traditionally use volume measurements. It's actually quite useful when you don't have scales available.

[mattkrause]

Home baking recipes do.

Anything aimed at professionals---or even serious amateurs---will be written as bakers' percentages, which lists the ingredients as a percentage of the flour weight.

Scales are great though. You just keep adding stuff to the same bowl: it's faster and there are way fewer utensils to clean.

[ReptileMan]

It's not for flour or yeast. Everything else that is not compactable you can get away with volume. But flour is different beast. Best to look at dough consistency if you know how it should look.