I have a new client who sold a rental property in 2020 after renting it for nine years.  She self-prepared all previous returns and the depreciation expense is essentially screwed up for almost all years, changing from year to year.  

For purposes of depreciation recapture, what should I do here?  Calculate the prior year depreciation as it actually was taken on Schedule E for every previous year?  Or should I calculate the "correct" depreciation expense and put the cumulative amount down?

Thanks in advance.