We include this requirement for organizations who may use one or two types of depreciation methods today, but who may expand upon that in the future. When they do, they need to be able to create and apply these easily without a consulting engagement. This implies that the product has an understandable formula syntax and form editor.
Scenario: A mid-sized manufacturing company utilizes CPM software for financial planning. One crucial aspect is keeping track of their significant capital assets like machinery and equipment, which depreciate over time. Currently, their CPM tool offers them straight line depreciation only.
Solution: They expand into a new market and must acquire machinery which requires a new depreciation methodology. They are able to create a new asset class in the planning tool with a new depreciation schedule. Now, then they add new assets, the system allows them to select this new method.
Ideally the system you're evaluating, assuming it has a Capital Asset module or function, will offer a depreciation schedule for just about every scenario. There are only so many.
We include this requirement because you may acquire a product that has what you need today, but 3-5 years from now you'll need the flexibility to add more. If this turns into a $10,000 consulting job, you'll end up doing it in Excel. That's bad for everyone. With that in mind, it is best if the system allows more of these methods to be added instead of marrying the user to what is included out of the box.