Keyboard ghosting on mac notebooks I recently bought a Retina Macbookpro and want to make sure I can keep it in good condition in the event I need to sell it in the future. Assuming the keyboard is not much different from the integrated keyboards of other computers in the product line; do you think I should buy a keyboard cover? It's not the type of thing I really want, but if it means avoiding wear on the keys' texture, I'll have to go for that. I know that the keyboards are back-lit, but do any of you with Macbooks or apple keyboards experience significant degradation of the keys into that oily look?
I own a late 2008 aluminum MacBook unibody machine, and I use it daily. There's no real "degradation" of the keys, though there's one smooth "polished" spot on the right of my spacebar, due to heavy use. 

I don't think you have anything to worry about. It's a laptop, the keyboard is meant to be used.