I have a registration form. The task is to add a custom field called, "Age" and it's a drop down field of a list of ages. I'm seeing lots of ways to do this but I prefer to get a professional opinion before I venture out. I am seeing a plugin in the Plugin Manager called, "Fields - User" and it's description says, "This plugin lets you create new fields of type 'user' in any extensions where custom fields are supported". What's the best way here? Are there any free extensions that help with this? What should my approach be?