In 10+ years the bulk, and thats like 98% of the footage i have taken from my dashcams, and i have for many years had both rear and side cameras too.
Well the front camera is where i get my footage, even if i have been rear ended 2 times and none of them was captured on video, but it was not needed, even the last time when i was hit while parked, after the timer i use had kicked in so no camera recording, but fortunately there was a little old lady that took the plate of the offender that of course just left.
The front camera 100% record all you do with your car in relation to a lot of things like lights / signs and curbs / lane markings, this will often be enough to disprove outrageous claims against you.
Mind you a rear camera are a bigger deal in the US as often the cars will just have a plate in the back of the car, so any oncoming car that do something stupid, well your front camera will just capture make / model, but a rear camera would at least have a chance of a plate capture when the oncoming car get back there.
I have owned cars for 40 years now, but i have only experienced those 2 rear endings, first time camera did not work due to poor power source and me being lazy / stupid, second time due to me using 1 hour cut off timer on parking guard, and my car get hit after being parked for 2 hours,,,,, i now use 3 hours on the parking guard timer.
So ! it is still pretty rare i have ever needed a rear camera in the great perspective of things.
BTW that first time, well i stopped for a girl wanting to cross a marked pedestrian crossing, like the law say i must in that situation, the car behind me also stopped just fine, but the next car the big Nissan 4X4, well the guy in there was on the phone or something so he just plowed into the car in front of him, shunting it into me.
NP though the guy took blame just fine.
Anyways my working front camera had me doing what the law say, so no one would have been able to claim brake checking or something else stupid to save their own ass.
As mentioned you can always add a #2 camera in the back, the only downside is you have to go to 2 places to get memory cards, but if you are not sharing too much / getting into too many crashes, that should be rare you need to go there.
