If your car is at least five years old, there's a good chance you can do without a collision policy, which pays for repairs to your own vehicle. Say your old warhorse has a book value of $1,700 and you pay $500 a year for collision insurance with a $1,000 deductible. If you total the vehicle in an accident, the policy will only pay out $700 -- barely more than what you pony up each year. Check your car's book value at nadaguides.com. If the annual collision premium is more than 10 percent of what you could sell it for, it makes sense to dump the policy. And if you own a new car that's still under warranty (check your owner's manual), take a pass on mechanical-breakdown insurance -- you're already covered.