Why hollow icons are more work for your users and ultimately create cognitive fatigue.
Recently, someone asked me to critique some new mobile work they’d done. The app looked pretty great overall, but some of the design was following the lead that iOS7 created precedent with. They were designing to “fit in” on the platform.
It motivated me to share why the practice of creating or using hollow/thin line icons in a user interface is, generally, not a great idea. Even to fit in on a platform.