So I plan on using the recorder in 24/7 mode while I would use the SD cards only for detections. That way, I can use smaller cards and won't have to replace them as quickly.
I have found that SD cards have come down in price so much over the years that, for me, they are a bargain even for the large ones. So in my photography hobby, I have settled on 256GB cards. I have a variety of them split between 2 brands: Samsung and Sandisk and so far, they have held up over the past 2 or 3 years with lots of photos taken.
The Sandisk ones are even marked as "High Endurance" and are advertised as "Ideal for dash cams and home monitoring systems". The best thing: they are cheap at
only $40 CAD.
My comment was not necessarily at recommending those 2 brands, but that SD cards are fairly inexpensive these days and perhaps you shouldn't focus on getting smaller cards because, unlike HDDs, if you double the SD card size, you're going to get double the life because electronic media has a limited life.
(A bonus for use in photography is that the larger SD cards are a lot faster and, importantly, stay fast until the end. I've had older 8GB and 32GB Sandisk Extreme Pro cards get slower and slower as they get fuller. For photography, this will mean that it will take longer to clear bursts of photos when the cards get fuller. I'm not sure if this has an impact for security cam footage. )
