I always thought keyboard covers on macs were not realistic unless removed everytime as there is not enough of a gap between screen and keyboard. However, I found on macs the keys get damaged very easily from oils, far more so than other laptops. I see the need for one, but it does damage the typing experience somewhat.

I've found the screen cover to be almost essential. I had 2 MacBooks where the screen was ruined by somehow making contact with whatever on the keys. Not sure how it's possible but the first thing I do now after buying a MacBook is put a glass screen cover over it.