The cliche on " location " is true. This relates to the liquidity of the real estate: will more or less people want to buy this property when I go to sell it? Also relates to long term increase in selling price verses property tax: Are the carrying cost so high it eats gross profit and no one will want to buy it? I tend to hold for 10 years or more- what expenses ( roofs, heating/ Ac, stuff like that) are you probably going to face over that time period.

liquidity would be one.

The returns aren't that great.