For which breads is slashing necessary?

Toast

I know that some breads require slashing and some don't. How to know which is which if there's no indication in the recipe? What are the criteria for deciding which breads will require slashing?

Also, if a bread does not necessarily require slashing, will it matter if I do anyway?

Thanks all.

Kim

Free formed, hearth baked breads with "artisan" crumb made from lean dough will typically be slashed.  Enriched pan breads with fine even crumb more often than not are not slashed. 

Usually 'lean' dough refers to dough that is merely flour, water, salt and yeast with no enrichments (such as fat or oil, diary, or sugar of any kind). The hydration level doesn't matter. Good guess though. :)

A 68% hydration dough is considered 'stiffer' than a 72% hydration. Higher hydration dough is 'wetter' or 'slack'.

Doughs that are very moist  and are liable to split and burst with the internal stream pressure ,

are good candidates to slashing a vent or two across .