I never put protection on my screen devices. One of those guys that never damaged a phone in my life. Had no problems with deck.

By that I mean, that depends on you and your track record. My wife would kill any mobile without a protective case in a month :p

I have one on my phone, but that's because the screen is constantly exposed. In my pocket, thrown on a desk, next to keys, etc. On a deck I don't think it's necessary as long as you're using the case. Just put it in it's case when you're done, keep the little screen protector it comes with on top of it and you'll be golden

I live life dangerously and don't bother with protectors. Neither the deck nor my phones!

You shouldn't put a protector on it. If you get a normal protector, you're basically just re-adding glare. If you get an anti-glare protector, you're further increasing the blurriness and darkening the screen, as that's how anti-glare works. The adhesive will also fill in the etching and reduce its effectiveness (search for "scotch tape frosted glass", same concept), but how permanent that is has never truly been verified; presumably, a good rub with alcohol should fix that problem.

I don’t use screen protectors and have rarely noticed an issue, even on phones. I do use a phone case partly for the occasional drop accident, and partly because the phones today have such a low friction coefficient that they’re a pain to hold or place on a smooth surface. I considered ordering one for the deck, but when I travel it’s in a case and when I’m at home it’s not being used as an air hockey puck, so I decided it didn’t really need it.

I do not. I'm not super careful with it, but I've had no scratches over the year(?) I've had it. It's mostly either been in the case or the VESA mount. However, I have had it on the window sill and the dog has stepped on it once or twice - maybe 3 times total. No scratches.

FWIW, I really prefer anti-glare but I find that many screen protectors anti-glare have a rainbow/static fuzzing that happens. That's why I like the etched glass solution, though it does carry more risks on a phone than it does for something that's usually more protected.