I moved into the lower unit (50%) of my duplex in 2018. I had renters there part of the year. I filed my 2018 taxes as usual, splitting supplies, taxes, expenses, etc., and claiming depreciation.
I did not claim any rental income in 2019 so there was no schedule E or depreciation report.
Then I re-rented the upstairs unit (I live downstairs) starting 1/1/2020. I know how to do the expenses, but not sure about depreciation. As indicated, I moved back into the building and occupied 50% of it after renting both units for the 12 previous years. I am thinking of transferring and hand entering the data as it stood at year end 2018, but I'm not sure.
This becomes challenging when the use keeps changing (personal use vs rental use or both).
In the asset section, my advice is to put the duplex on your return with original dates, then change the prior depreciation amount to include all prior depreciation deducted on your returns.
When you start the rental section change the use percentage to 50% for the current year, first by selecting 'I rent out a unit in a multi-unit property where I live'
In this situation I advise you enter the rest of your expenses and do not choose to let TurboTax split them.