Hierarchy decisions. Every report you will ever run is shaped by a tree somebody drew in the first week.
What the tree is for
Division, category, subcategory, type. The hierarchy is not filing — it is the axis every count, every margin and every sell-through will be grouped by. If it cannot answer the question the buying meeting asks, the answer gets rebuilt by hand in a spreadsheet every month.
Depth costs more than breadth
Each level you add is a decision someone has to make correctly on every article, forever. Four levels that are always right beat six that are guessed at. Add a level when a real question needs it, not in case one does.
One article, one place
If a garment plausibly belongs in two categories, the tree is wrong at that point — not the person filing it. Either the categories overlap and should be merged, or the distinction between them belongs in a tag rather than in the hierarchy.
Moving things later
Articles do get recategorised, and the system has to let them without breaking history. That is the argument for keeping the meaning in the hierarchy and out of the article number: a number that encodes the category cannot follow the article when the category changes.