What's most important when looking at Comps?

[Rob Carmody]

First and foremost, I know that estimating the market value can be a combination of and art and science. But I'd like to understand how most people find adequate comps when looking at a property (in this case, a SFH). What I've been doing to-date is looking at all RE that has been sold with the same attributes:

-- Same type (condo vs SFH vs MFH)
-- Within 0.25mi, 0.5mi, 0.75mi, 1mi (expand where necessary)
-- Same XBXB setup
-- +/- 20% sqft 
-- Sold within the past 3mo, 6mo, 1 year (expand where necessary)

I've heard of people calculating the $/sqft and using that to create an estimate, I've heard of people using same # bathrooms but ignoring bedrooms, I've heard of people prioritising Distance away vs. Sale Date and the opposite. 

What are your thoughts? How do you weigh what criteria is the most important when the results in the different scenarios can vary immensely. When do you expand your search and which levers do you expand first?