Did you factor in their move in costs?

My personal opinion would be to work the numbers starting with the rent, factor in your expenses, and determine your operating expenses.  

I never thought I'd have to factor in the potential of a NEIGHBOR being the problem instead of a tenant, but I guess that's the beauty of landlording.  

Also, I would have to factor PMI? 

Here are the details: Duplex built in 1999Target Purchase Price: $392,000Unit 1: 4 bedroom 1.5 bath rents for $2100/monthUnit 2: 3 bedroom 1.5 rents for $1900/month (we would occupy this side)Total monthly income: $4000Expenses:Principle + Interest: $1950Insurance: $100Mortgage insurance: $253Taxes: $720Vacancy (5%): 200Maintenance/repairs: $330 (1% home value/year)Cap Ex (5%): $200Tenant responsible for utilitiesTotal expenses: $3753 (this does not factor in property management as we will be owner occupying, however if I factor in property management at 9%, it would add $360 which would be negative cash flow).Total cash flow $257CAP rate: 6.4%Cash on Cash return: 9%Without property management we should have positive cash flow, given that I am estimated expenses correctly. 

What are the factors that should be considered?

The #1 factor in making money in class d/f areas is market knowledge and knowledge of how to deal with the issues that arise from investing in a high risk area.I grew up in a class d/f area, and Ive invested in those areas in the past.

I have an opportunity to get a SFR for 45k that is in a rough area but newly renovated with new hvac, water heater, and roof. rent should be 750 per month, taxes 650, ins 900. assuming 35% for capex and repairs and 10% for PM. assuming 8% vacancy factor and 5% leasing.

The hands on approach will help you and ease the fear factor in stepping in and doing your first deal.  

Please note, in the event of a legitimate lawsuit we do have liability insurance to cover any claims.This is an attempt to design a lifestyle and not necessarily the best mathematical return.