Cost Per Use

Cost per use is the single most useful framework for converting purchase decisions from feeling-based to data-driven. The formula is simple: total cost divided by number of uses. A $500 kitchen knife used 300 times per year for 10 years has a cost per use of $0.17. A $50 knife used 20 times and then replaced costs $2.50 per use. The inversion of intuitive “expensive” and “cheap” that this framework produces is its value — it forces specificity about actual usage in a way that sticker price comparisons don’t.

Cost per use is most powerful for the categories where the gap between purchase price and usage is largest. Gym memberships are the canonical example: a $200 monthly membership used 20 times per month costs $10 per visit, which is cheaper than most drop-in rates and represents good value. The same membership used twice per month costs $100 per visit — which reframes the “I should keep it, it’s only $200 a month” logic entirely. The subscription audit framework in subscription audit applies this logic at scale across all recurring costs.

For luxury and high-end purchases, cost per use often produces favorable numbers that justify the spend. A $2,000 blazer worn 100 times costs $20 per wear. A $300 fast-fashion alternative worn five times costs $60 per wear. The more expensive item is 67% cheaper on a per-use basis, which reframes the purchase decision meaningfully. This is the logic behind the “cost per wear” metric widely used in fashion analysis, and it applies equally to tools, equipment, furniture, and any durable good.

Cost per use is less useful for infrequent purchases where usage is inherently limited — a wedding dress will always have a high cost per use, and that’s expected. It’s most valuable for recurring purchases and membership costs where the usage assumption at purchase time is frequently optimistic. For the broader framework of evaluating whether a purchase is worth making at all, see worth it? The Smart Spending pillar covers cost per use alongside all the other analytical tools for intentional spending.