Quickbooks desktop is a powerful tool when things are working well but the program's ability to solve your accounting needs can be constrained by the data you have. There are a number of reasons why you may want to start a brand new file for your companies data. some of those are:
•QuickBooks runs slowly; upgrading to Enterprise may not solve this
•Data Damage; all efforts to correct have failed
•List Limits; All lists 14,500 (individual limits of each list is 10,500)
•Changing your EIN; changing from Sole Proprietorship to a Corporation
•Stop/Start tracking inventory; You cannot change inventory items to non-inventory part items
•File Size; QuickBooks are optimized for files of a certain size. Larger QuickBooks company files are prone to more incidents of data damage and performance issues.
Pro:10mb-50mb; Premier:50mb-300mb; Enterprise:3000mb and up