An important aspect of data ownership is that you can continue accessing the data for a long time in the future. When you do some work with local-first software, your work should continue to be accessible indefinitely, even after the company that produced the software is gone. “Old-fashioned” apps continue to work forever, as long as you have a copy of the data and some way of running the software. Even if the software author goes bust, you can continue running the last released version of the software. Even if the operating system and the computer it runs on become obsolete, you can still run the software in a virtual machine or emulator. As storage media evolve over the decades, you can copy your files to new storage media and continue to access them. On the other hand, cloud apps depend on the service continuing to be available: if the service is unavailable, you cannot use the software, and you can no longer access your data created with that software. This means you are betting that the creators of the software will continue supporting it for a long time — at least as long as you care about the data. Although there does not seem to be a great danger of Google shutting down Google Docs anytime soon, popular products do sometimes get shut down or lose data, so we know to be careful. And even with long-lived software there is the risk that the pricing or features change in a way you don’t like, and with a cloud app, continuing to use the old version is not an option — you will be upgraded whether you like it or not. Local-first software enables greater longevity because your data, and the software that is needed to read and modify your data, are all stored locally on your computer. We believe this is important not just for your own sake, but also for future historians who will want to read the documents we create today. Without longevity of our data, we risk creating what Vint Cerf calls a "digital Dark Age." Some file formats (such as plain text, JPEG, and PDF) are so ubiquitous that they will probably be readable for centuries to come. The US Library of Congress also recommends XML, JSON, or SQLite as archival formats for datasets. However, in order to read less common file formats and to preserve interactivity, you need to be able to run the original software (if necessary, in a virtual machine or emulator). Local-first software enables this. Martin Kleppmann, Adam Wiggins, Peter van Hardenberg, and Mark McGranaghan. Local-first software: you own your data, in spite of the cloud. 2019 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software (Onward!), October 2019, pages 154–178. doi:10.1145/3359591.3359737

In the fullness of time, the files you create are more important than the tools you use to create them. Apps are ephemeral, but your files have a chance to last. The ancient temples of Egypt contain hieroglyphs that were chiseled in stone thousands of years ago. The ideas hieroglyphs convey are more important than the type of chisel that was used to carve them. The world is filled with ideas from generations past, transmitted through many mediums, from clay tablets to manuscripts, paintings, sculptures, and tapestries. These artifacts are objects that you can touch, hold, own, store, preserve, and look at. To read something written on paper all you need is eyeballs. Today, we are creating innumerable digital artifacts, but most of these artifacts are out of our control. They are stored on servers, in databases, gated behind an internet connection, and login to a cloud service. Even the files on your hard drive use proprietary formats that make them incompatible with older systems and other tools. […] If you want your writing to still be readable on a computer from the 2060s or 2160s, it’s important that your notes can be read on a computer from the 1960s. You should want the files you create to be durable, not only for posterity, but also for your future self. You never know when you might want to go back to something you created years or decades ago. Don’t lock your data into a format you can’t retrieve. These days I write using an app I help make called Obsidian, but it’s a delusion to think it will last forever. The app will eventually become obsolete. It’s the plain text files I create that are designed to last. Who knows if anyone will want to read them besides me, but future me is enough of an audience to make it worthwhile. Steph Ango, File over App, https://stephango.com/file-over-app