Purchasing a duplex at retail. Good idea? Bad idea?

[Charles Conroy]

Our tentative plan is to buy a duplex in our Denver metro area market, rent out the smaller half while updating the the side we live on then vice-versa. Eventually moving out and renting bother sides. Punching the numbers seems to be good cash flow opportunity overall even with the high market we live in. 
Good idea or bad idea? Should I leave as is and not spend money on upgrades other than paint and other cosmetics? 
This would be a first time in this process for us, any tips or insight would be helpful from those who have done it.