Closet shelves are NOT one size fits all. Ideally, they should be a variety of depths based on what each section needs to store. Builders commonly put in shelving that is 11 Â¼â deep. This default measurement doesnât work for all sections of a closet and certainly wonât fit every homeownerâs storage needs.Custom closet designs typically allocate 12â for hanging sections and shoe shelves.deally, they should be a variety of depths based on what each section needs to store. Builders commonly put in shelving that is 11 Â¼â deep. This default measurement doesnât work for all sections of a closet and certainly wonât fit every homeownerâs storage needs.