The mobile phone has slowly developed into a single recognisable object that encompasses many different brands. They live off they idea that now the user is used to phones having a large front screen, WiFi connectivity, ability to call and text, battery and their very shape. For a user to buy an iPhone 5 it is inferred that when the iPhone 6 comes out the user will be able to smoothly transition into the new phone with little hassle. That is because there has been a trust relationship built on how they consistently use similar aesthetics and functions to make the user feel more comfortable.
The guitar has divulged into three different types, acoustic, electric and classical and they all have similar consistencies to the point once you are a master at one, picking up another variant is easy to do because the functionality of all three are slightly different. All guitars have the same core components built like, bridge, neck and neck. these ideas vary very slightly which gives a user pleasure that the next guitar he buys, he will be able to buy something of similar style
Computer keyboards Have kept the same layout for decades to keep their functional consistency. Many may differ from size, colour, height adjustable, arm rest addons, USB (Universal Serial Bus) female ports, lights, program-ability, storage and if it has or hasn’t got a numpad. But the core functionality of the layout of the keyboard has stayed the same due to the nature of our use of keyboards. We use them to type and we develop muscle memory from them which increases our typing speed and consistency. But if you swap the “A” key with the “P” key the users functional consistency will be severely hampered because he has learnt how to type soundly on a traditional keyboard.