Claims on multi car policies are usually dealt with similarly to single car policies. All multi car policies are different so it’s important to check with your insurer, but the best multi car insurance policies will not penalise one driver if another makes a claim. If someone else on the policy makes a claim, for example if your partner makes a claim on their car, your no claims bonus will not be affected.
The 12-month policy will generally start on the date that the last car insurance is up for renewal, with short-term cover used to protect the other cars in the interim. For example, if you have one car that needs to be insured from February and another in June, the February car will be insured first but the policy will actually renew in June when both cars are covered. After the last car has been insured for a full 12 months, the policy will renew each year until you choose another policy.