At Snap, we recommend sub-branding, as part of an integrated branding strategy, only where a company has a number of different products or solutions that need to appeal to a variety of different target customer groups. This might be because the client is offering essentially the same solution but packaged and priced differently for different customer types or demographics.
Again the same tools are deployed as will a main branding exercise, but overlaid with the complexity that comes with the requirement to research and understand the specific needs and motivations of each consumer type.
because...... it's all about getting your foot through the door