Don't have a tiny deductible

When buying auto insurance, consumers frequently think of it as a way to protect themselves against every ding and scratch. That's a bad idea. "You should insure for what you cannot afford to lose," says financial planner Jeffrey Bogue of Bogue Asset Management. That means, don't have a miniscule deductible of $100 or even $250. "If you nickel-and-dime the insurance companies with these small claims, you may get socked with a premium hike or they may say 'we're not going to insure you,' " he says.

Policies with higher deductibles (Bogue says $1,000 is often sensible) that extend to higher coverage levels are not necessarily more expensive and protect drivers from costs associated with more serious car problems. Higher-deductible policies also cost less.