Cost per use can make a durable purchase easier to compare, but the result depends on a number that is easy to exaggerate: how often you will actually use it. Dividing a high price by hundreds of imagined uses can make almost anything appear economical. Begin with your present routine rather than the routine a product advertisement suggests.
The basic calculation divides the relevant ownership cost by the number of uses you reasonably expect. Include necessary accessories, maintenance, and other costs that differ between the options. Do not add speculative resale proceeds as though they were guaranteed. If resale matters, examine it separately as an uncertain possibility.
Make the assumptions visible
Consider two bags in an illustrative example. One costs 120 and might be used 60 times; another costs 200 and might be used 100 times. Both would cost 2 per use under those assumptions. The figures are invented, and the expected lifetimes are not product claims. The calculation does not show that the second bag is better: it shows which assumptions must hold for the comparison to work.
Ask where the usage estimate comes from. If you carry a work bag several days each week, recent habits provide a useful starting point. If you are buying equipment for a hobby you have not tried, frequency is far less certain. A borrowed item, rental, or smaller initial purchase may provide better information than a confident spreadsheet.
Test more than one scenario. Calculate the result at your expected use and at roughly half that use. If the purchase only looks reasonable in the most optimistic case, treat that as a reason to reconsider. This simple sensitivity check is more informative than adding decimal places to an unreliable estimate.
Keep quality and affordability in the decision
Some features matter without fitting neatly into the formula. Comfort, ease of cleaning, repairability, and suitability for the task can affect whether the item gets used at all. Compare products that can genuinely perform the required job. An uncomfortable shoe does not become good value merely because its theoretical cost per wear is low.
The upfront payment still matters. Two products with similar projected cost per use can place very different demands on this month's budget. Do not use a long-term calculation to ignore an immediate spending limit.
After ownership begins, notice actual use without turning every occasion into accounting homework. If an expensive item stays in the cupboard, the useful lesson is about the buying assumption. For the next purchase, improve that assumption rather than forcing unnecessary use simply to make an old calculation look correct.