What questions to ask when buying a duplex?

[Eric P.]

This would NOT be an owner-occupied property.  A house recently hit the market, the location for me is perfect (around the block from my handyman/property manager), price is right, and potential rents are perfect.  Needs updating but looks to be all cosmetic most of which I can do myself (rip up carpet for hardwood, wood panel walls, and needs a few appliances).  What are some questions I should be asking when considering a duplex?