I’m sure you have heard the old expression GIGO – garbage in, garbage out. There will be information that you need to capture that is specific to your business. If you don’t have a specific custom field in your database to capture that, each person will put that data wherever they can. I’ve seen people use the Address 2 field or Country field to keep track of secondary email addresses, for example. The reasons you should customize the database is to data is entered consistently in the right fields. This is critical for reporting as well as database mining – aka. Looking up the data you need.