Icons in user interfaces are the elements that cannot be overestimated. When a pixel-perfect icon set is used well in an app or on an app, it can help guide users through the product, add a pleasing aesthetic to the overall design, and create visual consistency. On the other hand, when icons are designed and implemented poorly, the user can create a negative experience for the user, and it will result in miscommunication or confusion even though we have a strong UX design.
When I design apps always I draw a big picture of what kind of icon style can engage with other UI elements. It should be simple, legible, same line weight, and same geometry. Also, they look like they belong to the same family. Each icon set represents the different look and feel created for SlingPlayer, Dish Anywhere, and SlingStudio.