Most insurers — and we're not just talking about auto insurance companies here — use some type of credit-based insurance score to help determine how risky a potential customer is. The practice is a bit controversial, which is why some states have laws against using it (see above). But the general thinking behind insurer credit checks is: If someone is bad with their finances, they might be irresponsible in other areas of life, too. You can learn more about how car insurance rates are determined here.
It's hard to say. You might see rates change as you age, but they don't always go down, so much as they level out or increase at a lower rate. (Remember, the rules of inflation are in effect.) And that assumes you don't incur any red marks on your driving record. As for a change in marital status, you generally have to contact your insurer to get a rate decrease — and if your spouse has a less-than-stellar driving record, well, again, you mind wind up paying more.
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