Up until recently, well recent in my dashcam timeline at least, i just used mental notes when and where something happened, but this meant i had to pull the memory card right after the drive if there was any chance of my abused brain remembering anything.
With newer cameras i have resorted to just use the event button and then only pull the card once every month or so, only newer cameras i test i look at the footage more often.
I especially like the way SG cameras do their event recordings, most cameras deal with a short buffer ( 20 seconds or so ), meaning if you want to save a event you better hit the button right away.
But my SG cameras deal in recording segments instead ( i use 3 minute ) so when i press the button lets say 1 minute into the current recording segment, it will get saved but also the previous segment, alternative if i am 2 minutes into the current segment when i press the event button the current one will be saved but also the next one., so in case of the SG camera i get 2 X 3 minutes saved,,,,, from each camera and it is a 2 channel system a total of 12 minutes are locked away, or 2 X 3 minutes from both front and rear camera.
A camera using old style buffer might only have 20 seconds from before event and then say 30 seconds after, which i feel can be very little, but again - again, not a huge problem as what are before and after the event are in among the regular files, i just feel it is more convenient to have it all locked away with no chance of it getting deleted, even if i always run plenty large memory cards ( only use 128 and 256GB cards now )
This i feel is convenient as in case of something where you might be freaked out a little, you do not have to rush to the event button to have the actual event locked away safe, so you can pull over, compose yourself, and then hit the button, and the event + the lead up and some aftermath should still be safe in the read Only / event folder.
The buffer style cameras TBH i only think of their event recordings as "flags" of a event, parts of it might be outside of the saved event recording, so in among the regular files where there are a chance of it getting deleted,,, not least if you have a very small memory card, with a ample sized one, this are less of a problem as you will have to record for many hours still before the part of a event outside of a locked file might be in danger from deletion.
Some brands have also started to deal in segments, viofo for instance now lock the whole segment too, but just the one being made right then the event happen, so if your event are right at the end of the segment and say you still record 3 minute segments, well you have say 2.5 minutes from before the event, and then 30 seconds with the event and after, but then it end and you will have to look for more of interest in the regular files,,,,,, which is also fine again if you have a ample sized memory card.
Some brands even respectable well know ones, will still sell you a high end dashcam with a 16 GB card,,,,, IMO that is outrageous.
You can under extreme duress make do with 64Gb for a camera / each camera in a system, but really IMO you should go for 128 GB