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Insurance
The arithmetic of expected value, why the answer is usually no, and the narrow cases where a warranty genuinely pays.
By FreeCalculators Editorial · Published 2026-09-01 · Updated 2026-09-04 · 4 min read · 945 words
An extended warranty is insurance against repair cost, and like all insurance it is priced so the seller collects more than it pays out. That does not automatically make it a bad purchase, because insurance is worth buying when the loss would be unaffordable. It makes it a bad purchase for losses you could absorb, which describes most of the items extended warranties are sold on.
Multiply the probability of a covered failure by the cost of that repair, and compare the result to the warranty price. If the price meaningfully exceeds the expected loss, and you could pay the repair from savings, buying is a losing bet you did not need to take.
Retail extended warranties are frequently priced at several times expected loss, because they are sold at the point of purchase where the buyer has no ability to compare and the retailer earns a large share of the price as commission. That margin is the reason they are pushed at the till rather than advertised on price.
| Item | Warranty price | Failure chance in term | Repair cost | Expected loss |
|---|---|---|---|---|
| Laptop, 3-year plan | $220 | About 12% | $450 | $54 |
| Large television, 4-year | $180 | About 8% | $400 | $32 |
| Washing machine, 4-year | $160 | About 18% | $320 | $58 |
| Smartphone, 2-year | $150 | About 25% | $280 | $70 |
| Used car, 3-year | $2,400 | About 55% | $2,900 | $1,595 |
| Home HVAC, 5-year | $1,100 | About 35% | $4,200 | $1,470 |
The first four rows are clear losses: you pay three to five times expected loss for a repair you could cover from savings. The last two are different. A used-car warranty and an HVAC warranty both cover failures that are reasonably likely and expensive enough that many households could not absorb them immediately, and the pricing is closer to expected loss.
That is the actual dividing line: not the item, but whether the loss is affordable and whether the price is near the expected value rather than a multiple of it.
Self-insuring the small stuff for a decade (2026)
Household buys five covered items over 10 years
Buying every warranty
Laptop x2 at $220 $440
Television at $180 $180
Washing machine at $160 $160
Smartphone x3 at $150 $450
Total premiums paid $1,230
Actual repairs needed in the decade
one laptop screen $310
one phone screen $240
Claims value received $550
Net loss -$680
Self-insuring instead
$12 a month to a repair fund $1,440
Repairs paid from the fund $550
Fund balance remaining $890
The self-insurer is $1,570 better off and still
has a fund for the next failure.The self-insurer did not get lucky. They kept the seller's margin instead of paying it, which is the structural advantage of self-insuring anything you can afford to lose.
Check before buying anything. Manufacturer warranties often run a year or more, some credit cards extend a manufacturer warranty automatically when you pay with the card, and homeowner or renter policies may cover certain sudden damage. Buying a warranty that duplicates existing coverage is the most avoidable version of this mistake.
Consumer protection also matters here. The Federal Trade Commission enforces rules on warranty disclosure, and its guidance on service contracts is a reasonable place to check what a seller is required to tell you. If a salesperson will not hand over the contract terms before payment, treat that as the answer.
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How this guide was created
This guide was written and reviewed by FreeCalculators Editorial, drawing on published formulas, official government sources, and real calculator outputs from our 4 calculators in this category. Every claim is sourced; every formula is auditable. Read our review policy.