What determines how many hooks a bra will have?

I think heavier-duty bras have more hooks. My more supportive bras tend to have 3 hooks, and I haven’t worn one with a single hook since I was in a B-cup.

@Seelix is correct. Generally the bigger the cup size, the more hooks.
One of mine has 6 ;)

The front hook styles have many hooks. The back fastening ones depends on the width of the strap. A skinny strap would only take one, my full figure support bras take four.

@papayalily it is a sports bra similar to this .

@wilma O.O Wow, I’ve never seen one designed like that.

This has five hooks in the front. No seams, no wires and very comfortable. It works well for those of us who are post-lumpectomy and have breasts that are two different sizes.

I have six of them and have thrown away all my other bras.