Also be aware that credit cards may have time limits. I found that my Visa had a 2 week maximum coverage. I broke a windshield in New Zealand during a 3 week week rental and wasn't covered.

 

I travel and rent cars about 2 or 3x / month. Credit card (Amex) covers with 0 deductible. I have had a couple minor incidents in rental cars and it never cost me a penny. Aside from credit card - personal insurance covers for most regular rentals - there are exclusions for trucks, off-road, etc. so check. So, generally your risk with a rental car is no different than driving your own - and even less if your credit card covers you.