You can easily reclaim 1–2 GB of space, which is massive on a 16 GB device.
Commands you may need (via terminal/SSH) filza file manager ios 935
: Since iOS 9.3.5 is an older firmware, many modern apps won't run. Filza lets you inspect Info.plist files to attempt compatibility tweaks or modify app assets like icons and sounds. You can easily reclaim 1–2 GB of space,