Accountant needs fair market values for cost seg study?

[Jeff Costa]

I am talking with my accountant about the mechanics of a cost segregation study on two duplexes purchased in 2022. He has asked for fair market values for items that will be included in the study (ex: roof, water heaters, HVAC, cabinets, appliances). This data will be used to prorate the purchase price based on the relative fair market value of each of the components. I know the age of some items, but not all (ex: kitchen cabinets, sink, carpet) items. Two questions:
1) Do you simply estimate the age of unknown items?
2) Where can I source fair market value data of components? Ebay?
3) Is it common for owners to provide the fair market value data?

Note that the accountant is not located in the same city as the duplexes, which may be the problem here. I would appreciate guidance from anyone who has done a cost seg study. Thanks in advance!