The cost-per-use lens for purchases

Sticker price is the least useful number

A $2,000 espresso machine and a $4 coffee from a cafe look like they belong to different price universes. Across five years of daily use, they don’t. The espresso machine works out at about $1.10 per cup; the cafe coffee costs $4 per cup every time. The more interesting question isn’t “how much does this cost?” but “what does each use of it cost me?” — a framing that strips out the difference between a one-time payment and a recurring one and replaces it with a single comparable number.

The cost-per-use formula

Cost per use is the total cost of ownership divided by the total number of uses over the ownership period:

(upfront cost + ongoing costs − resale value) ÷ total uses

The three inputs are where most amateur analyses fall down:

Upfront cost is the full purchase price, not the financed monthly payment. Financing shifts timing, not total cost (and usually increases it when interest is included).

Ongoing costs are everything required to keep the item in use: subscriptions, consumables, maintenance, electricity, insurance, storage. Many purchases have a higher ongoing footprint than buyers estimate — a gym membership without the monthly charge is just a door pass.

Resale value is the realistic price you’ll receive when selling, not the optimistic one. Electronics, fitness equipment, and musical instruments typically sell for 20–40% of purchase price after three to five years; cars and appliances higher. Some categories — most textiles and small electronics — have effectively zero resale value.

Where the method earns its keep

Three purchase categories benefit most from a cost-per-use lens:

Gym and fitness. A $80/month gym used twice a week costs roughly $10 per visit — competitive with a casual pass and cheaper if usage is higher. A gym used twice a month costs $40 per visit, which is often more than a drop-in fee elsewhere. The number exposes whether the commitment matches the behaviour.

Appliances and kitchen gear. A $600 stand mixer used weekly for a decade costs $1.15 per use — trivially cheap. The same mixer used four times a year because it turned out not to suit your cooking style costs $15 per use, a figure that makes the purchase look poor.

Subscriptions and memberships. The monthly charge is the trap; the right figure is per-actual-use. Streaming services watched nightly are excellent value; the one forgotten in the account that renews annually is pure waste regardless of how “affordable” the monthly charge looks.

The break-even line

A useful mental reference point is the $1-per-use threshold. Anything that gets cost-per-use below $1 with honest inputs is typically excellent value — the per-use cost is low enough that opportunity cost is negligible. Between $1 and $5 per use is reasonable territory for most discretionary goods. Above $5 per use, the purchase needs to deliver disproportionate enjoyment or utility to justify itself; above $10 per use, most such purchases are better replaced by paying for each use individually.

Where the method breaks down

Cost-per-use is a cost lens, not a value lens. It can’t see joy, aesthetic pleasure, or the subjective weight of owning something. A painting you look at every day has a cost per viewing that may be negligible, but most people don’t buy art on a per-viewing basis. Use the method to rule out purchases that clearly fail the arithmetic, not to overrule purchases where the arithmetic is borderline but the non-financial value is high.

The method also undersells occasional-use essentials — a fire extinguisher used zero times across ownership has infinite cost per use, but the purchase is trivially worthwhile. Safety, insurance-type, and low-probability-high-consequence items live outside this framework.

Next steps

Use the cost-per-use calculator to enter upfront cost, ongoing monthly fees, ownership period, expected usage frequency, and resale value. The output is a single headline cost-per-use figure plus supporting totals — a clear way to pressure-test whether a considered purchase actually earns its price tag.