Every input should have an output.
For the past two years, I have worked on a few different products ranging from Small Business CRM's to online business plan builders. As requirements and features are documented and created, it's very easy to overlook why certain features are requested or added. Sometimes you have to ask yourself (and others), what is the benefit of this feature?
To borrow a technique from Robert Dempsey (found while searching how other product managers document requirements) I created a Google document for each product that we have, and document the following requirements before we bring a feature to development:
It was this simple thought process that led me to another simple question to ask yourself: For every input, what is the output? In other words, the feature is asking me to input information, what will the output be? This doesn't apply to every product, but is especially the case in CRM, where reports are imperative and users rely on the system/software to tell them where their opportunities and sales (output) are based on the information (input) the user puts in.