Seems to clear whatever cache that I can't do manually, and has restored my phone to original performance.
I leave my phone on 24/7, and haven't turned off my current LG Leon LTE since I got it several months ago. After a month or two, it started to get slow in general UI navigation. Functions would run fine, but it would take relatively forever to go from page to page within an app even. I used to leave my desktop on for days at a time, and at least with XP it would get slow after a day or so. Shutting it off/re-starting it fixed this. I finally thought to do this with my phone, and it similarly fixed it. This may be particular to my LG Leon LTE, but it might work for you if in the same or similar circumstances.
I leave my phone on 24/7, and haven't turned off my current LG Leon LTE since I got it several months ago. After a month or two, it started to get slow in general UI navigation. Functions would run fine, but it would take relatively forever to go from page to page within an app even. I used to leave my desktop on for days at a time, and at least with XP it would get slow after a day or so. Shutting it off/re-starting it fixed this. I finally thought to do this with my phone, and it similarly fixed it. This may be particular to my LG Leon LTE, but it might work for you if in the same or similar circumstances.