The importance of a property's age?

[Brandon Roof]

How big of a role does the age of an available property play in your decision making when deciding whether or not to proceed?  Where does it fall in importance (i.e. cash flow is more important than age but central air isn't) and do you have any parameters that you operate within (i.e. won't consider any properties over XX years old?  What would a property need to have in order for you to look beyond the age?