If you change the primary use of an item
If you buy an item exempt to use in a farming or ranching activity, it becomes taxable if you stop using it in a farming activity. You must then pay tax on the fair market value of the item.
Note: The opposite isn’t true. If you pay tax on an item because you use it in a non-production activity, you can’t claim a tax credit if you begin to use it in a production activity.