Let's say you don't think digital will survive so you print everything (that you consider to be at the time of printing) important.

You:

• choose decent quality papers and inks, maybe even the best you can afford
• use a high quality printer
• use folders and boxes that won't quickly degrade
• regularly keep up your printing and storage supplies
• keep your boxes in an appropriate climate
• protect against damage from fire, water, and animals
• move all of your printouts every time you move, or make provisions to have someone manage them on your behalf
• continue to pay your paper, ink, printer, folder, box, storage unit, housing, and moving bills
• find someone to take custody of your printouts after you die and manage them at least as well as you did

While you're doing all of that, take a moment to stop and ask yourself, are these printouts being preserved because something inherent in the physical properties of paper makes them survive, or because you've decided it's worth investing time and money to make sure they survive? Then ask yourself what it would take to preserve the things you didn't, or couldn't, print but that you still want to be kept.