If you record continuous + triggers, then it will record substream until triggered and then mainstream while triggered and then go back to substream. The substream doesn't use as much storage and even though not mainstream quality, it is better than nothing if the camera didn't trigger for some reason.
Many people here are of the mindset if it happened more than X weeks ago (where X could be a week or 3 weeks), then it probably doesn't matter.
If you have your alerts and notifications set properly and you have full coverage around your house, you will know fairly quickly if you need to look at something. If a neighbor comes and asks you if you caught anything about 3 weeks ago...well unless you are zoomed into their driveway or house, best case is maybe you can say oh I saw a flashlight at 3am on such date, but other than that it would be useless anyway...and unless they can give you an exact date and time, are you really going to scrub thru days of your videos for something that your cameras probably couldn't identify anyway? And if you help all your neighbors, no reason for them to get cameras LOL...
I used to be of the oh just record triggers and have months and months of video, but I never would look at it and if I did it ended up missing whatever it was I was looking for.
Further, 24/7 allows the overview camera to catch peripheral activity around you that motion detection wouldn't capture (unless set way too sensitive). Neighbor car like 6 houses down got sideswiped by a drunk in middle of the night. My overview picked it up blurry at that distance, but noise of collision was captured, so I could get the time and was then used to tie the car to my LPR and the police was able to track owner down.
Without that 24/7 all I could have done was provided a list of plates of vehicles that night.
