I inherited an instance with too much customization. As an example, the sales order has 15 workflows, 14 client scripts (ouch) and 22 Server Scripts. So many custom fields, and several custom forms. I start with a Google Spreadsheet, listing every object, its function, looking for duplicated solutions, conditions no longer met, etc. Then slowly consolidating scripts and the like. Do you have a framework for this cases? How To's, Tips, Tricks, Best Practices.