From personal experience once you're over 45, car insurance is relatively cheap and stays that way for quite a few years, even with claims irrespective of fault, how do I know One of the biggest factors in the premium is where you live other than age.
I've found multicar policies a con because they are difficult to compare when the various policies initially start on different dates, then after the first year they've tied you into one renewal date for all of your cars and then hike the price. I've always without fail found it cheaper to use comparison sites and to buy individual policies. Currently we have 4 cars & 2 motorbikes in the household, maybe those with only 2 cars can save money, but it'd be very surprised if this was the case over the long-term.