Your ability to drive success in your Salesforce.com adoption is directly related to how simple and cohesive your Salesforce.com database has been set up. This process is one which needs to be continually refined after the initial customization. This is natural as usage invariably lends itself to greater clarity by your users.
However, changing your system without an overall attention and commitment to focus and clarity can cause you to have an overengineered system. If your database becomes more about data entry than about productivity, action and results, then users typically wane in their enthusiasm and alignment.
Within Salesforce.com, it is important to recognize the relationship of data. How a page is laid out, the types of fields created, the relationships between fields, data object creation and relationship and reporting need to have a systemic and logical integration. If you create new data objects, then the impacts across your system as well as the extra work created within your user workflow need to be evaluated as part of integrating the requirement or simplifying to something with less steps.
It’s easy to make the simple complex. Salesforce.com success relies heavily on thinking in terms of systems and interactions to make the complex simple. It is what I do a lot of when working with Salesforce consulting clients. Be sure to have a good understanding before overengineering Salesforce.