Dividing the price of a garment by the expected number of uses produces an indicative measure, not a certain value. Frequency depends on personal preferences and conditions. The comparison can help to discuss the purchase, as long as the hypothesis remains visible and is not presented as a guaranteed result.
I propose to distinguish the uses already observed from those only imagined. A similar garment already owned can offer a reference, without insuring the same behavior. Any costs of care or adaptation may also be relevant to personal evaluation.
In a hypothetical example, two products have different prices and different predicted frequencies. The comparison changes if one remains unused because it is inconsistent with real occasions. A very optimistic estimate can make any purchase seem convenient.
The measure serves as a question about how the product will be used. It does not establish environmental qualities or benefits on its own. Its value lies in making explicit the relationship between spending and expected use, leaving the customer the assessment of taste and their needs.