ContractorTools allows you to enter estimate items that have a quantity but zero costs, but when you sync with QuickBooks, those items do not get written to QuickBooks. Why?

There are a number of reasons for this. One has to do with how estimate data is represented in ContractorTools. ContractorTools has separate "buckets" for materials, labor, equipment, subcontractor and other costs, but, for efficiency, it only stores data in any of those buckets if a cost is entered. In other words, ContractorTools doesn't store cost records for items with no cost, so when it syncs that item to Quickbooks, there's nothing to write. 

It is conceivable for is to make ContractorTools write zero cost items to QuickBooks, but since there is no cost entered, the program would not know what type of cost to write to QuickBooks when writing zero costs, so it would have to write an estimate item for all cost types. In other words, if you entered a zero cost item in QuickBooks, it would appear as 5 zero cost items in QuickBooks - one for each of materials, labor, equipment, subcontractor and other costs. We think that would be confusing. 

If ContractorTools is used for estimating and invoicing, and QuickBooks is only used for accounting purposes, in which case zero cost items would have no significance, we believe this should not be an issue.