I like number 3 on this list. Some communities in our area treat small multi-family properties as commercial property. Imagine buying a fourplex and finding out you are required to have a fire sprinkler system that has to be inspected yearly and maintained. Then you find our the city requires that you provide the water and garbage. Best to find these things out before you buy. Call the city before you make that big purchase and find out if there are any special requirements that you will be subject to.