A motor insurance quote is an estimate of what a policy will cost the insurer, plus a margin. Everything on the application form exists to sharpen that estimate.
The premium is a predicted claim cost
Insurers hold large records of policies and the claims that followed, and they model how the characteristics of a policy relate to the cost that resulted.
A quote is that model's expected claim cost for the applicant, with expenses, reinsurance and profit added on top.
No premium predicts an individual's future. It prices a group of similar policies, on the understanding that most will claim nothing and a few will claim a great deal.
Vehicle characteristics carry substantial weight
Repair cost matters as much as accident likelihood, so parts availability, body materials and the presence of sensors in bumpers all feed into pricing.
Vehicles are placed into groups reflecting repair costs, performance, security and typical claim experience for that model.
This is why two cars of similar value can be priced very differently, and why an inexpensive vehicle with costly repairs can carry a surprising premium.
Driver and location factors are correlations
Age, licence tenure and claim history are used because they correlate with claim cost in the data, not because any individual is being judged.
Location matters through local claim experience, which reflects traffic density, theft rates, weather and even how many claims in an area involve disputed liability.
Which factors may be used at all is constrained by regulation, and permitted rating factors differ substantially between jurisdictions.
Excess and cover level move the price directly
A higher voluntary excess transfers the smallest claims to the policyholder, and small claims are numerous, so the effect on premium is larger than the amount suggests.
Optional cover for courtesy cars, legal expenses and breakdown is priced separately, and each is a small insurance product in its own right.
Mileage and use also enter the calculation, since exposure to the road is the most direct driver of the chance of a claim.
Renewal pricing follows different logic
A renewal quote reflects the same risk model plus the insurer's assessment of the book of business and its costs for the coming year.
Rules in several markets now restrict charging existing customers more than an equivalent new customer, which has narrowed a long-standing gap.
Because insurers weight factors differently, quotes for the same driver vary widely between companies, and comparing them is the only reliable way to see the spread.