Sooner or later every format goes digital. Audio recordings. Video recordings. TV signals. Photography. Books.

That’s a wonderful thing, right? Digital means instant access. It means infinite duplication without loss of quality. It means instant transmission around the world. But unless we get diligent in a hurry, it could also mean a hit to our cultural record keeping.

Consider photographs, for example. We know what people looked like 150 years ago because the prints—yes, an analog format—are still around.

What photos does anybody print these days? Only a few special ones. We view the vast majority of digital photos on screens. That’s convenient, they look great, and they’re often much bigger than 4 × 6 prints. But will they be viewable in 50 years, let alone 150?

That would be assuming a lot. For one thing, it would assume that the JPEG format used by most digital photo files will still be around in 150 years. JPEG has a fighting chance, because there are so many billions of photo files, but it’s not a sure thing. No computer format has been around for even 50 years.

The situation is even more grim when it comes to less mainstream files. Preserving video, for example, is going to be a nightmare. In the short history of digital camcorders, we’ve already accumulated a vast array of file types—MPEG-2, AVCHD, MiniDV, .MOV, .AVI, and so on—and that’s not even counting the millions of dying tape formats they’re stored on. What are the odds of these videos being playable in 50 years, let alone 100?

Already the current version of Microsoft Word can’t open some documents from the first versions of the program. Do we really expect to be able to play AVCHD videos in 100 years?

Let’s not even get into e-book formats. These book files (from Amazon, Barnes & Noble, Sony and Apple) are incompatible, proprietary, copy-protected—and brand-new. You really think that their copy-protection schemes or even the companies that invented them will still be around in 150 years?

No, when you buy a copy-protected book for your Kindle or Nook or iPad, you should assume that what you are buying is a temporary right to read—not the book itself. There’s not much chance that you’ll be passing your book collection down to your children or grandchildren, as you might with real books.

Whenever I write about format loss and data rot, a few enterprising companies always pipe up. “We’ve got a new Web site called EverStore—we’ll store your digital files forever!” This is hilarious, considering that the Web as we know it isn’t even 20 years old. Not a single online-storage company has been around for more than 10 years—and several have already gone out of business, including big-name services such as AOL’s Xdrive. If you really think that the EverStores of today will keep your files safe for your grandchildren, well, here’s a brochure for my Brooklyn Bridge Investment Trust.

In other words, in the rush to record humanity’s stories in digital formats, it doesn’t seem as though we are giving equal thought to how we are going to preserve them.

It’s not hopeless, though. It’s just going to require a lot of work. Prints from 100 years ago have reached us largely by accident; we may stumble upon caches of them in attics, for example. But in digital, nothing happens by accident. Nobody is going to stumble across the photos on your hard drive in 2061, that’s for sure. (What hard drive have you owned for even 10 years?)

If, indeed, we care about sending our recordings into the next century, we’ll have to tend them like a garden. Consumer magnetic tape begins to deteriorate after about 15 years, so the time to convert your old audio and video tapes to digital is right now. Giant hard drives are cheap these days, and Google has plenty of tutorials on how to rescue those memories.

The next step is to make a commitment: that you will revisit your recordings every 10 years. If your digital files are to reach your great-grandchildren, somebody, or generations of somebodies, will have to copy them from one hard drive to the next and from there onto solid-state drives, then to nanotubes, then to brain implants—whatever the latest storage medium happens to be. And it’s not just the storage medium that will change; the file formats will have to be migrated, too. AVCHD probably won’t be the state of the art in video recording in 2021, but there will certainly be software that can convert it to whatever is.

That way some of our photos, videos and ­documents will reach the audiences of 2161. Maybe only a tiny percentage—but enough to make your descendants grateful that you made that once-a-decade effort.