The developer preview of Android 7.1 hit a number of Nexus devices just yesterday, and now everyone is going through the OS to see what exactly Google has added in this new version of Android and also finding out what exactly is being left to the Pixel and Pixel XL, and not coming to the Nexus lineup. One of the new features is called 'Smart Storage', and it does exactly what you think it does. It intelligently frees up space on your device, when you are running out of space. It's something that happens to all of us. Say you want to download a new app, but you don't have enough space to do so, Smart Storage will make it possible for you to download that app.
The interface for Smart Storage will look pretty familiar to features built into other smartphones that are designed to eliminate clutter on your device. There are three sections here, basically. Photos & Videos, Downloads and Apps. With Photos & Videos, you can opt to remove those photos and videos that are over 30 days old. This is definitely a great thing, especially with the ability to backup everything to Google Photos these days. That way the pictures aren't gone for good, but you are able free up some space on your device. Downloads and apps will show you which of these haven't been used for 90 days. Let's face it, if you haven't used an app for 90 days, it probably doesn't need to be hogging up space on your smartphone right now. There's no cache cleaner here, which is probably a good thing, as those don't really do much to help you save room. As your phone will just rebuild the cache the next time each app is open.
Google has done a great job here at making the UI pretty easy to understand, even for those that aren't tech nerds. It also shows you how much storage each action will free up. Which is going to help you determine whether you want to remove that old app or not. More importantly, this appears to not be a Pixel-exclusive feature, as this is already on the Pixels, but it is now in Android 7.1 proper. So it should, theoretically at least, come to other Android devices that are running stock-ish Android (like Lenovo's Moto brand) when they get the update to Android 7.1.