I rented a Nissan Altima fairly cheaply from an independent outfit in Vancouver and returned it 10 weeks later with around 8,000+ miles added to it. I'd basically driven it to Florida and back in a roundabout sort of way, during a 12 month break from work to travel round the world. The guy did a huge double take when he checked the car over (it had only had about a thousand on it when I picked it up). No problems though. Even got free coffee cups with the name of the firm on them for being such a good customer!
