The main thing to be aware of is the oleophobic coating on your iPhone's screen.
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Another patent showed how Apple could keep future displays smudge and fingerprint-free using an oleophobic coating.
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Using a screen protector also means you don't have to worry as much about the oleophobic coating.
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Another less trumpeted but typically thoughtful innovation is the addition of an oleophobic coating to the touchscreen that repels greasy smeary fingermarks.