Hello, I got my S4 about 6 months ago and have been happy with it (I was an iPhone user for many years prior). However, I have noticed that lately it has been running a bit slower. The clearest evidence is when I exit an app and the main screen is blank (except for the wallpaper) for about a second or two (at most). I then watch the icons fill up the screen (maybe another second). This is not a big deal, but why would it do this when it was running much quicker since I got it? I have "normal" wallpaper (just a blueish background) I don't think I am running anything that is a power hog. I haven't installed anything new or fancy in a while. I do have Battery Doctor which kills apps running in the background - as far as I understand. Any advice of what could be causing this and/or what I should be looking at? Thank you.