Attribute set

Most systems label the attributes positionally, so the first attribute is not interchangeable with the second. If colour is first on some styles and size is first on others, every report and every automated match has to work out which is which per product. Pick one order and hold it across the catalog.

Use the fewest that describe a genuinely separate sellable thing. If you never stock more than one thickness, thickness is not an attribute, it is part of the product name. Adding an attribute you do not vary multiplies the variant count without adding information, and every one of those children then needs a barcode and a stock line.

Most POS systems cap the set at two or three attributes. Design within that limit rather than discovering it halfway through building a season.

The attribute set determines the shape of every child in the group. Adding an attribute after the fact usually means the existing children have no value for it, and systems differ in how gracefully they handle that. Where a change is genuinely needed, treat it as a migration with stock and sales history in scope, not as an edit.

The practical advice is to decide the set once per category, write it down, and apply it to every style in that category from then on. Wetsuits get colour, size and thickness. Boardshorts get colour and size. That decision made once at the category level is far cheaper than made repeatedly and inconsistently at the style level, and it is what lets a report compare like with like.