I been getting a great response because in my opinion the yellow letter is more "personal" unlike postcards where everything is "computerized".

I took them both to approval letter and the corporate office where I hang my shingle stated they did not like the idea that I wear both investor and realtor hat.

So my answer is .... it depends on what you want to do, just be sure you understand what all is involved in hanging your own shingle on the door.

Sounds like you have a retail contractor.I can get a 4 unit building that is almost 5,000 sq ft completed with hardy and labor and materials for 8,000.On the roofs you have to pay attention to number of layers put on it and also hail damage,bad run routes for water drainage and flashing and caulk issues.Here is Georgia you can have a 20 year roof but because of our weather extremes the expanding and contracting will wear out the roof shingles much faster.

Or are they run down, paint and shingles peeling off them, with iron bars over the windows and broken down cars parked on the dead lawn?

IMO, far more annoying is when these same people with no real knowledge or experience or expertise decide to hang up a virtual shingle and begin brokering notes, or as some gurus call it, “brokering cash flows”.

Best case, this guy is a novice who hung out a shingle hoping to make a quick buck. 

If shingled, make sure there are no missing shingles or deterioration on the top which may be addressed down the road.

This may include examples such as maintaining the landscape, a minor plumbing repair, doing shingle repair on a leaky roof or painting a few rooms between tenants.

After a recent fire, we learned the shingles were not covered.