Flash memory if you write backups on it infrequently.

Hard drive for general use.

>>51817618
Honestly you should be more worried about which standard will still be around in 15+ years.
A USB-C external hard drive is probably the best bet.

>>51817985
I dont see sd cards or usb going anywhere. Cards have pretty much stagnated to sd and we still have support for usb 1 which is like 20 years old.

>>51817618
None of those are ever alive to begin with.

>>51820732
What do you recommend as an external portable storage device then?

>>51820794
Mexican Maid.

>>51821175
Too expensive for too little capacity. Also only lasts like 60 years at most

>>51821190
>Too expensive
You're getting ripped off then, they are the cheapest.

>Also only lasts like 60 years at most
So what? Get another one halfway down the road.

>>51821236
Adress the small capacity issue too.

>>51821257
>for too little capacity
Your dick is tiny so it doesn't matter.