Dashcams have been around for a long time now and keep getting better, the early models had fairly low image quality and were even worse at night.

The latest dash cams are very different a lot of the cameras available have 4k video capture and excellent night time function.
they are fairly straightforward to operate and have a wide range of features including GPS which can prove where you were driving and how fast.

People often purchase a camera and just plug it into the cigar lighter socket and never even set the date making the footage almost useless as evidence.
The best way to fit a dash cam is have it professionally
installed and hardwired which involves connecting directly to an ignition live supply in the vehicle fuse box. This ensures that the dash cam is on as soon as you start the vehicle and off when you switch off the ignition.