If you use the same photo (from your Sonlet library) for your duplicate items, they will group together when you sort the leftmost column called "item". *

So when you receive a new box of leggings, sort into two piles: 'duplicates' and 'needs to be photographed'. New duplicates in the same box go in both piles--one 'to be photographed' and the rest in the 'duplicates pile'. Photograph and upload the new prints and then go through the stack of duplicate items, find and select the photos in the STR library, and upload them separately. 

You can leave all but one duplicate in 'Inventory' with the correct size and style selected. Using attributes** simply assign the attribute "restock: yes" to the items that are duplicates. You can see the attribute in your sales page, so you'll know when a duplicate sells and you can go find the match in your inventory page and list the replacement item. And it's easy to see how many you have left by sorting by the left column (the photos); when you use the photo library image; they all group together. When you're listing the last one, simply remove its "restock: yes" attribute. 

Need some more info on attributes to make this work for you? Check out the attributes Knowledge Base article and video tutorial here

*Is it a pain to find the same photo? ...yes. Is it worth it to have duplicate leggings in a list of 500 next to each other? ...absolutely. 

**Attributes are a relatively new feature. They are preferable over using the previous patch of the style and size identifiers: 'Duplicate' because attributes can be bulk-edited while in listings or inventory (unlike the style and size on an item) and offer more flexibility and customization. The old option of "duplicate" as size and/or style is time consuming to adjust and causes some unwanted outcomes--like all the duplicate leggings posting to the top of the leggings album, for example.