It is simply not enough to only keep a copy of the final signed contract. The correspondence leading up the final document is of immense value and in a dispute can clarify an issue swiftly. In a he said/she said situation, having the written correspondence leading up to the problem at hand will bring about a quick resolution to the problem. For that reason, and many more, email is a business tool that will stand by you and will keep you connected to your company, your client