I would say you always need a screen protector. These things are the first thing I put on it to prevent scratches. I do it with my cameras, phone, tablet anything that could be dropped or something sharp dragged across it like a ring or your watch. The Zagg is a self healing military grade cover that heals itself if scratched. After a long time you can just peel it off and get another one if you notice the screen isn't as bright bu I don't think they yellow and I don't notice any difference in clarity or brightness.

I think so. You may need to get the micro USB to USB adapter that Samsung sells for $39. I use it to hook my camera up to the tab and it reads it just fine and I can take pictures from the camera to my tab s. I also hooked up an external drive to the usb and it started to read it. There are so many files on there though that it was going to take a long time. But, I bet if you get a keyboard/mouse combo that uses the same usb adapter it should work. I haven't tried hooking up a usb hub to the tab s to see if other devices would work with it all at the same time. I wish the tab s had hdmi out. I don't need it with my smart tv because both have screen mirroring. But, for another tv i have that doesnt; have that it would be great to be able to cable it up to an hdmi out. I could get google chromecast but then you have to use your wifi signal. would be great if you could go wifi direct too.

There is a cost. But you will find it very easy to install