Some ContractorTools users have tried copying all cost items from their custom costbooks into their job templates so that when they create a new job, all of their cost items will be there and all they have to do is enter the quantity of the items they need for the job. There are a couple of problems with this, and there is a better way to accomplish the same thing.
One problem with copying all of your cost items into your job templates is that then the prices for the cost items in the templates would not get updated when you update the prices in your custom costbooks.
But there is a bigger problem...
ContractorTools stores all of your data in your device, and changes to the data are synced with other devices over the internet. In the years that ContractorTools has been in use, we have observed that this all works fine until a database gets up into the range of 40 to 50 thousand total estimate items (for all job). At that point the data syncing begins to bog down. 40 thousand items is plenty for a company that operates with say 80 active jobs with up to 500 items in each job - that's a pretty big company and 500 items is a pretty big job. And ContractorTools has a data archiving function to allow you to easily archive old jobs out of the database but still be able to access them if necessary.
The problem is, if you added all of your costbook items to your job template(s), then every time you create a new job, it would copy all of the costbook items into each job. It is not unreasonable to have thousands of items in a costbook. Each of the Craftsman costbooks have 10's of thousands. We have had users try copying their costbook items into their job templates, and the problem is that their entire list of custom costbook items gets duplicated every time they create a new job, so the database quickly fills up with thousands of items that are not actually used, but they are there consuming space and especially data syncing resources. This quickly overloads the data syncing process, so it grinds to a halt.
If you only have one device (and one user in your company), and have no intention of ever syncing data on multiple devices, then you might go ahead and try this. If you do, there is a way to bulk delete all of the "zero quantity" items in a job after you are done creating the estimate.
A Better Way
But there is a better way to accomplish the same thing. Presumably, the reason you would want to copy all of your costbook items into a template is so you could quickly scan through the template and only enter quantities to the items that you need in the job. The reason you don't need to do that is because you can copy multiple items (from multiple different item groups) at a time...
When you tap + to add an item, the "New Item" form appears. This allows you to copy from a costbook (Craftsman, or custom), or another job, or job template (or even an archived job). When you select any of these, you will notice that the items and item groups will have a little circle displayed to the left of the name. This is a checkbox. Tap the checkbox to select the item (or item group) to be copied. Notice that you can select any number of items, or item groups to be copied before you tap "Copy Items" (in the upper right corner).
Note: You cannot copy item groups from the Craftsman Costbooks, so there is no checkbox circle next to item groups in the Craftsman Costbooks.