Humanity views the world visually and we have a transformational experience on our phones. Design is everywhere but sometimes we don’t notice, everything we use is designed in some way.
When Ian Splatter was working for Instagram to redesign the logo and app he asked for three months where his team could work in peace and silence in a darkened room, where they could go through various possibilities and ideas and could better everything that they were working on. Splatter would get his team to draw the Instagram logo from memory within 10 seconds at the start of each meeting. This helped reveal a lot to them as they started to see peoples designs and also noticed similarities between the sketches the main similarity being that almost everyone remembered the rainbow dash at the top of the old Instagram logo. 
This eventually led them to the current design that is used today. As well as simplifying the logo Splatter also simplified the actual app and features by stripping everything down and taking away the colours used within the app. This change made peoples photos the centre of the user experience, When the redesign first launched, everyone hated the logo and update, Instagram received a lot of backlash from everyone but now its iconic to their brand and personally I can not see it any other way.
They refer to their designers “product designers” as designing is not just about the user experience but it can also be about the product strategy which is something that the designers also have to consider. The designers have to think about how things connect, move and flow.
Redesign is very important to get right and it usually requires a lot of testing. When done bad it can cost a business, an example of this is when Snapchat updated their app and it ended up costing them $1 billion. Redesigns needs to be embraced by the community, it needs to be liked by the people more than what came before it.