@henry r.I inherited a Sec 8 tenant in my first property that I also occupied, and quickly learned that it's similar to unemployment standards in that if you lose your job, you need to prove that you are at least looking for a job to get renewed.  

We were still the lowest rent in town, so we didn't lose any tenants. 

If that was the case then the duplex would be better, on paper any way, but then on the other side the duplex is spreading your risk over only two units so if you loose a tenant that is half of your income, where as in a quad when you lose a tenant its only 25% of your income.

You can be fined and lose credit access for failing to obtain proper authorization before investigating an applicant's credit history.

If you decide not to increase rents for several years, you will be losing value on your asset.Remember, if the market begins to decrease, tenants will expect you to lower rents.Gino

The one in Lakeland, FL that turned a ghetto house into $1500 cash in my pocket, the call from Kissimmee, FL that has a $10-25k flip potential, and one message asking to take their name off the list (which is better for me because I don't want to spend anymore money marketing to people who have 0% response rate anyways).Just be light and conversational to your sellers and buyersYou make your money on both ends of the deal, so negotiate the heck out of your seller's price (but be respectful and don't risk losing it) and use a realtor to give you true competitive comps on your sales price so you have supportive evidence for your price and cant get haggled too far down by your buyers, because they will try.Every cash buyer on my list wants their deals to be acquired at 70% of market value, including purchase and rehab.

Although I love these things, I don't like the noose around the neck feeling of the debt and many years of hard work to pay for the toy that loses its value quicker then you can pay them off.  

You know they are unlikely to lose their job and calling their CO if there is a problem often times help resolve the issue very quickly.  

His rents are way under market, the only people who are willing to rent from him are those that can afford that low rent, he knows the judge who does the evictions on a first name basis, he cannot afford to ever repair his properties, and he is seriously behind on property taxes to the point of losing some of them.Not only that, but despite being 70, he mortgaged his home recently to cover debts from the slumfolio, to the tune of several hundred thousand!

The though of losing their deposit however usually is enough to get them to clean up and fix.