Forget Storage, If You Want Files to Last Try Movage

I'd suggest the complement to this is emulation. I have an emulator for my old CP/M environment. I understand there are several emulators for Mac OS pre-10 stuff. DOS emulators and modern virtual environments galore.

So, don't just move your data. Make sure you also include emulation applications/environments. You may end up with a set of matryoshka (Russian stacking dolls). But, if you drill down through them, you will always be able to access your data, even when in proprietary format. And with the continued increases in processing power, the old evironments remain usable even through the emulation.

I guess a few notes on how to use the emulation, might be well worth it as well. So that 5 years later, you have some reminder of how to connect the bubble gum to the bailing wire.

Open formats would be better. But you don't always get those, nor their continued maintenance and support.