I have a dash cam in my car and also one in my wife's car. The one in the wife's car is quite low quality, narrow viewing angle, you can can't make out much detail, and it's basically useless at night. However I only paid about 25 bucks for it, and it' seen going for over 3 years. The better dash cam is in my car since I do more driving, it has a wide viewing angle, and will pick up details, it's ok at night time. I only paid about $45 for this one, and it's been working for over 2 years. Each is set on a 2 minute loop and each go about 45 mins before starting to record over the first loop again.
I have them for reasons similar to those already mentioned. I don't want it to be my word against someone else and come up on the losing end when I am in the right, that would piss me off to no end. I also have it in the event that I can use the footage to confirm what happened in an accident that I'm not directly involved in. Also in the event some jackass is driving like a maniac I have evidence to provide to the police.
Remember to use high speed memory cards in any dash cams you have, I started out using a class 4 in the cheaper dash cam and it seemed to record at about 8 frames a second, I upgraded to a class 10 and it works much better. I'm not much of a techie, so this was the first time I realized that memory cards have different speeds..but now I know.
