It is interesting how everyone prefers to save almost all the footage taken.
I have been shooting photos for more than 15 years. I shot say 300 pictures in one trip, but mainly edit and save 40 to 80. And I am a semi professional, so I do not shoot everything I see, but try that every photo be perfect! Then, after editing, I save the edits (because obviously that are the best in technical quality, composition, colors, telling a story, etc.). The remaining pictures, generally I delete them all, because after years I realized that I never come back to them again.
Now I have been shooting videos (and photos) with my MP for almost two years. And I apply the same principle: Delete everything that did not pass the edit-phase.
I know it is hard to delete precious material. But think about it: How often do you watch older unedited footage of lower quality? Maybe you think it might be useful for edits you may do in the future. Think again: How often do you come back to old footage to make a new edit of those?
Definitely it is a personal thing. But this is my experience...
Regards to all and happy filming!
Different people take photos and videos for different reasons and I'm the opposite of you, while I like to try and take decent photos and videos the real value of them is the memories. There's many photos I took of my previous dog that I'm proud of particularly those of him leaping through the water with all the droplets perfectly frozen but what surprised was when he passed away, those weren't the shots I was drawn to it was all the boring, often poor quality photos I'd taken of him around the house when I'd got a new camera or lens and was practicing with it to get better as I badly missed seeing him around the house. After that I started using a digital photo frame and these days I have a beautiful 4K tablet as a digital photo frame which has around 20,000 photos loaded on it from the last 20 years to randomly jump through.
I bought my first action camera when I first started getting into mountain biking, I took a lot of long boring videos that I stuck aside and didn't look at for years. Then when i was going back through those videos I loved seeing them again, the people who'd got me into cycling I hadn't seen for years, how utterly rubbish I was at mountain biking, seeing what a lap looked like on the first endurance race I did, watching me completely muck up a duathlon transition and almost crashing with cramp. I stopped taking videos for a while because what's the point when they just sit there but their value is later on when the memory has faded, it really frustrates me the gaps when I didn't bother using the camera.
As much as it upsets me to admit it my current dog is getting older as he'll be ten years old in a few months and when does pass away, I know how much I am going to enjoy going back to my first Mavic clips when I was taking him out each day for a walk and practicing with the drone. He absolutely adores the drone and while many of those videos are worthless to make a pretty edit, they're worth it to me to see him look so excited and happy as he watches the drone. And it's not just him either as the area I used to practice with the drone even in the last couple of years has changed completely, it was a wide open spot perfect for the drone but now the trees have grown to a good height I don't fly the drone there any more whereas they've been chopping down the trees on the other side so within a couple of years it's going to look completely different to my early Mavic flights. Which I'll forget until I watch those videos.
It all needs a reasonable amount of storage but the price of the storage is a fraction of the price of the equipment that took the photos and videos and it's easy enough to have multiple backups these days even without online storage. The value of the photos and video are far more because once they're gone and can never be replaced.
In reference to hard drive failure rates people are quick to complain about Seagate drives based on very small sample sizes, BackBlaze is a cloud storage company who buy many of these drives and their first choice is usually Seagate which don't have a high failure rate. In fact last year their stats showed WD as worse than any other Seagate model they had but the reality is all of them have relatively low failure rates. By far the worst drives for me personally have been Western Digital but wouldn't affect my decision in any way when choosing a new drive, the only reason I don't have any at the moment is they don't produce consumer 12TB or larger drives.
I've worked with thousand of hard drives at work including extremely expensive enterprise grade fibre channel hard drives and I've seen failures all over the place, what's crucial is you should never trust any brand of hard drive with your data and it should always be backed up in at least one location separate to the main drive. Also RAID 1 is not a backup solution, it's a common mistake made and unfortunately one I've had to explain to people when their data is gone. The reason for RAID 1 (where data is mirrored across the array) is to provide continual uptime when a drive fails so it's particularly useful for a server but a separate backup solution is required, this is because what happens to one drive happens to the other so if data is deleted, corrupted or encrypted by cryptographic malware it's potentially lost. There's also further issues I've seen such as a drive failing silently in the array so you don't realise that the redundancy is gone and you're running on one drive so when that drive fails, the whole array is gone and so is all the data.
Tl:dr - I keep all my data and make sure you back up what you don't want to lose