What is the general consensus on screen protectors? I really like the feel of the glass and I think the plastic smudges easier and I've never used them; but is that a mistake on my part? The guy who sold me my Gnex actually applied one on my screen; while watched and wondered if i should stop him. So far I've left it on; even though I'd really prefer to take it off. Are they really necessary? I had a Droid for years and never put one on that phone and never scratched the glass.