A cluttered hard drive is a cluttered mind. (I think Albert Einstein said that.) If you’re constantly fighting against a “Low disk space” warning, it may be time for a little spring cleaning. Here’s how to find out what’s taking up space on your PC or Mac—and what to do with the files you just can’t let go of.

Analyze Your Hard Drive for Storage Hogs

Before you start deleting things willy-nilly, you should step back and look for the big wins. Deleting a bunch of 50-MB files here and there isn’t going to make nearly as big a difference as cleaning out an 80-GB folder of old TV shows or uninstalling a few games. (Seriously, if you’re a gamer, clearing out old titles can free up huge chunks of space instantly—be honest about what you’re actually going to play. You can always reinstall later.)

If you’re on a Windows 10 machine, open up Settings > System > Storage to see a breakdown of your drive and which folders are taking up the most space. You can click on any category to see more information, especially in the “Other” category, which will show you individual folders with large files in them. Find stuff you don’t need anymore, and get rid of it—it’s not always easy, but this is the best thing you can do to free up space.

If you’re on a Mac, you can analyze your drive for large files by clicking the Apple menu in the top-left corner and going to About This Mac > Storage. Click the Manage button and you’ll see different categories in the sidebar that you can select for a list of large files. Right-click files to delete them, and empty the Trash when you’re finished.

If you find these tools a little too basic, third-party alternatives like WinDirStat and Disk Inventory X can dig even further to find out exactly what folders and files are using your storage space. You might find old iPhone backups you no longer need, videos you might have stored in the wrong folder, or disk images from that old Raspberry Pi project. For most people, the built-in disk analyzer will be fine, but these third-party tools can be helpful if you have large files hidden in more unconventional folders.

Clean Up Temporary and Duplicate Files

You’ve probably heard this advice before: Both Windows and macOS store temporary files like thumbnails, old update packages, or cached internet files that you can delete to free up space. And that’s true, but I’m going to be a bit of a buzz-kill here: These files will eventually come back, as that’s how the system is designed to work—these caches help your computer run faster. So while this might eke out a bit of extra space for the time being, it’s not a permanent solution, and it probably won’t free up nearly as much space as cleaning out your own vault of personal files.

In Windows 10, click the Start menu and search for Disk Cleanup. You’ll be given a list of files you can delete, at which point you can just click OK to free up that space instantly—or click “Clean Up System Files” for a few more options.

A new feature called Storage Sense can do some of this automatically. Head back to Settings > System > Storage, and at the top, click the Configure Storage Sense link. This will give you some options like deleting temporary files older than a certain age, or moving rarely used files to OneDrive (more on that in a moment). Flip the switch at the top to On when you’re done, and choose how often you want Storage Sense to run. Personally, I like to keep this off and manage things myself, but to each their own.

Useful reference for domestic helper.