why residual income? version, example, someone

Sunshine4ever

Hi guys..

So far I can only see residual income as as a gay ass backwards version of the DDM...

Now I am sure there is more to it, else CFAI would not have dedicated a chapter to the topic.

Can someone give an example of a case where I would really want to use residual income? I know the book gives bullet points about when to use residual income, but it is just not connecting for me.