Photography

Tip for you all who don't know it already. Most flash and solid state storage will try to keep the number of writes per 'cell' the same. So first use it will start writing across the memory and even if you delete images/files or format, it will keep progressing and writing to consecutive cells until they've all been used once, then back to the beginning for write 2 as you keep using it.

You won't generally find any sold state storage these days which some cells have significant 'wear' and others have not.

So, buy the biggest SD/CF/etc you can as it will generally last longer. It also has the side effect that the larger cards usually have a bit faster read/write speed for the same class rating.

I did once see a device which was effectively an external hard drive with built in battery and CF/SD reader. When you plug in a card, it would copy all the data to the drive, verify it, and optionally delete it from the card. If I was stuck with a single slot body, I'd look for something like this as a backup. If I didn't find anything, I'd get a Raspberry Pi with battery and create my own version, possibly with 4G/5G connection to the cloud backup as well.