Choosing a higher deductible reduces the premium on almost every policy, and the reduction is larger than the arithmetic of expected losses alone would suggest. The reason lies in which claims the deductible removes.
Small claims are the most common ones
Loss distributions have many small events and few large ones, so most of the claims an insurer handles are at the lower end of the range.
A deductible eliminates all of them, which removes a large share of claim volume while removing a much smaller share of total money paid out.
Because each claim carries fixed handling costs regardless of size, cutting the small ones removes administrative expense disproportionately.
The premium reflects expected cost plus loading
Pricing starts from expected losses over the policy period, then adds amounts for administration, capital, distribution and the uncertainty around the estimate.
The loading is not proportional to claim size, so shifting frequent small losses to the policyholder reduces both the expected loss and a meaningful portion of the loading.
This is why the premium saving from a higher deductible often exceeds the average amount the policyholder would expect to absorb.
Deductibles change behaviour as well as cost
A policyholder facing the first portion of any loss has a direct interest in avoiding small incidents and in not claiming for trivial ones.
Insurers treat this as a feature rather than a side effect, since it reduces both the number of claims and the losses themselves.
The same reasoning explains coinsurance arrangements, where the policyholder retains a share of costs above the deductible rather than none at all.
The structure varies by line of business
Property policies commonly apply a flat amount per claim, while some perils carry a deductible expressed as a percentage of the insured value instead.
Health coverage often combines an annual deductible with per-visit amounts and a ceiling on total out-of-pocket cost, which produces a more complex shape.
Whether the deductible resets per claim or per policy year makes a substantial difference to what a policyholder faces in a bad year.
The choice is about exposure, not value
A higher deductible transfers risk back to the policyholder, so the relevant question is what loss could be absorbed without difficulty rather than which option looks cheapest.
Very low deductibles convert insurance into a payment plan for routine expenses, which is expensive because those expenses are certain rather than uncertain.
The terms available, and how they are regulated, differ considerably between jurisdictions and change over time, so a policy's own wording is what governs.