I had some very dangerous close passes & now run cameras on my commute and leisure rides.
I look forward to grabbing shots of beautiful sunrises etc, and I sometimes make videos of rides for my own pleasure.
At the time, my main reason for getting cameras was to provide evidence - if the worst happened to me or I was injured. It felt like a real possibility.
Now reporting is easy in Avon & Somerset, I take the opportunity to report bad driving. It pays off when you see the same drivers on your commute being much more careful. Asking nicely (and I rarely catch up with the drivers anyway) is rarely productive.
I do pull over on narrow roads and let drivers pass from either direction, I give way wherever possible, I'm well-lit, I smile & wave thanks, and yet there's a dangerous minority who won't drive with due care. Asking these ones nicely simply does not work. They need to know that actions can have consequences.
I have a
https://passpixi.com/ which made a big difference to close passes - didn't eliminate them but has reduced the frequency.
My helmet camera is a Drift Ghost XL on old firmware. It's been good and costs about £150 full price, there are frequent offers on them, or CEX sometimes have used ones with a 2-yr warranty on them for £90 or so. A bit of a lump on the side of the helmet but it is visible to drivers and has good enough quality footage for most needs, although no image stabilisation. It does very well on battery life - 7-8 hours or so. I'd recommend it. Drift's customer service can be slow but they get there in the end. It helped me to have an old firmware version for the best reliability and image quality.
At the back I have a Magicshine SeeMee DV light/camera combination which takes good if bouncy footage and has a long battery life again.
My son has a Chilli Tech camera on his helmet which is fine during the day, but hopeless at night.