While it's true almost no one wants to pay extra for a car rental, sometimes the insurance add ons can be very smart buys. A lot will depend on what your private auto insurance covers, but when it's needed, renter's insurance can be a real lifesaver.

The best bet to make sure you have the right rental car insurance coverage before you sign a lease is to check with your private insurance company before getting a rental. In many cases, private insurance will cover a lot, so the add on buy might not be worth the expense. However, the only way to know for sure is to ask, so make sure to do so.

If you do need rental insurance, you'll find there are several different types you can buy. Let's take a look at the main types of add on insurance:

Collision damage or loss damage waiver: This type covers everything, including the deductible, in the event of a crash. This might not be needed for some private insurance policy holders, but it can be a real money saver in an emergency for those who do need it. This coverage is generally fairly inexpensive. Do remember to check with your company before buying this type. It's very possible you already have it. If paying by credit card, also check with the credit card company before buying this option as some credit cards cover this, too.

Personal accident coverage: This insurance option covers accidental death and medical situations for the renter and passengers. Many times this coverage is not needed as personal insurance on your own car tends to travel with you. Be safe though and ask before you turn this down. It generally isn't very expensive, but what it covers can be.

Property coverage: There is an option that will cover all your belongings in a rental car from such things as loss, theft or even destruction in an accident. Again, private auto insurance policies will generally travel to the rental car and cover these things, but do find out before you turn it down. This type of auto coverage is generally pretty cheap, and it can be very welcomed if it's needed.

Liability: Here and again this type may not be necessary for those who have their own private insurance, but it's a very important coverage if it's needed. Liability covers you from claims made by others for injury, death and/or property damage.

Many of the major dollar rent auto insurance coverage types available might not be necessary purchases if you have good private auto insurance, but it pays to find out. Being covered in a rental car can be a very big deal if there's an accident or theft takes place. Nothing can ruin a vacation quicker than an uncovered accident. Check with your insurance company to be sure, and if you're not covered, cheap car rental insurance can help.