Generally Accepted Accounting Principles (GAAP) allow companies to choose any inventory costing method, although the consistency principle requires that they not switch between methods on a regular basis. However, many companies still change methods from one year to the next. Perform research on this topic in order to address the below questions. Make sure to cite your sources:

1. Why is consistency important in the first place?
2. What are some valid reasons companies may decide to switch methods?
3. How does the company's choice of financial accounting inventory method impact their tax reporting?
4. What financial statements does the inventory choice impact and how may a change impact those statements?