Why it matters
Your contracts with your customers lay down the terms on which you work for them, and how they pay for it. Therefore, having a dusty signed agreement in a filing cabinet is missing an opportunity. With the terms of a contract, or even the original document, at your fingertips, you will know what your customers' expectations are, as well as what services you can charge additional money for.
E-mail or text message reminders to renew a contract
Running a help-desk?
Offer your clients token-based support. It's a good way of helping them use your support resource wisely, while separating support delivery from the commercial relationship.