Your personal auto-insurance policy might cover liability and collision, and most homeowner’s policies cover the loss of personal effects from rented vehicles (make sure yours has an off-premises theft rider). Keep in mind, however, that whatever liability limits you have on your auto insurance will also apply to rentals, and that some personal policies don’t include collision coverage. Some credit cards, including most issued by American Express (the parent company of Travel + Leisure), provide secondary coverage that kicks in only after a renter’s primary insurance, such as a personal auto policy, has been exhausted. Frequent renters may want to consider a credit card that provides primary collision coverage, such as Diners Club and select Visa cards. The premium car-rental protection plan from American Express, priced at $19.95 per rental, gives cardholders one-time primary damage-and-theft coverage (up to $75,000), as well as coverage for accidental death and dismemberment, medical expenses, and loss of personal property. (If you pay $24.95 per rental, coverage increases to $100,000.)