Tactility is extremely important for me with electronics, and screen protectors get in the way of that. Likewise, these colored plastic case thingies that people clip on their phones or Macbooks get in the way of it too. Of course without all this mumbo-jumbo, equipment is going to develop hairline scratches and wear over time but it's crazy to obsess over it. You're supposed to be using the gear, not ogling it like a masterpiece in an art museum.
I take appropriate precautions like using a laptop sleeve (Waterfield, as it's the only one that fits well enough to provide protection in a bag in which I'm carrying other stuff as well), but that's as far as I'll go.