How long should a video be?

For a few years I said that the ideal length web video for a retail brand was 3 minutes, then (based on analytics) we saw that consumers were only really watching the first 90 seconds. So the advice changed to create shorter, higher impact videos. NOW, analytics are showing that (in most cases) videos of 60 seconds are the ideal length for people. So what are the reasons behind this? 1. Mobile - with the desktop and laptop market shrinking, more people are consuming video on mobile devices such as phones and tablets. The simplicity of search and play is creating a flick to the next behaviour. 2. Environment - whilst people are watching video content on the move, we have to take in to account the noises and distractions happening off device. We can deal with a few things within the video - clean audio at good levels and uncomplicated clear visuals. When creating text to appear in-vision, take in to account that the person watching may have an iPhone, so make it of a size that