Analysis of older duplex

[Mitch Waltzing]

So here is the situation I am pondering and seeking advise.  Looking at duplexes, and most of them that are appealing are built in the 1930, up/downs. Most of the up units have the the roof line showing in the units (my assumption is that this is not desirable to live in).  So if I would purchase these duplexes would I be constantly overturning them/ sitting empty.

My number: vacancy 8, matanance 8, with property managment 8, capex 6, and cashflow is 200.  With the information I provided is there anything else I should be considering when looking at older duplexes.