is property Values in your area. IF you lived there a long time, you know the area and have seen the changes taking place. If you haven't lived there long,go to open houses and look at what selling/how much/ in your area. Look at for sale ads at prices /areas and rent rates.
How may times did you say to yourself, "I saw that property and could have got it for a good price" or it sold for XXX amount and you know they made alot of cash....and THEN you see it has turned into a car dealership or resturant or whatever and someone took ACTION and is making the money YOU could have made!!
You MUST take action after you learn the VALUES of properties and see deals.