As a general idea, taller shelving conveys a sense of a bigger volume of products, with a wider selection and lower or discounted prices. Shelving at a lower height says more high quality, bespoke products, more expensive and limited selection, with a more intimate shopping experience. You can use this guide to add a variety of different feature points in your store, to add sale areas, speciality areas and broader, more generic areas to shop in. You can also use this to segregate sections and create departments.
Ceiling height shouldn’t make a difference to the height units you choose, so base your choice on the products you sell and the impression you want to convey to your customers.