Thanks Morry!
I have a few thoughts on comps...
Sources:
1. Active Listings - give a good sense of competition. Doesn't necessarily tell you what prices are though, as at least some listings will be overpriced - which is while they are still listed. MLS is best source, but Redfin, Zillow, etc. work in a pinch.
2. Pending Listings - give a better sense of what is actually selling, and the list prices that attract an offer. That said, they don't tell you the actual selling price, so you have no idea if they were overbid with multiple offers, or the seller excepted something far below asking. MLS is best source.
3. Solds - These are the most important, and the basis of appraisals. Here I strongly recommend public records. MLS is ok, and can be a little faster for the most recent sales, but MLS is incomplete and reliant on the agent that enters the information. Public records will include off-market sales that aren't on the MLS, and will reflect actual sales prices. Prior to this month not all sales had prices, but starting 2015 you can no longer hide the tax stamps, so prices will be shown for all sales.
4. New Homes - If there is ANY new home activity in your area it is super important to keep tabs on their pricing. I learned this one the hard way when I found out one of my listings was sitting because of a new home development down the street that was undercutting the resale market. Unfortunately this was back in 2006 when market was changing rapidly - its a mistake I won't make again.
5. FSBOs - Yep you are competing with those two. Doesn't hurt to keep an eye on craigslist and yard signs.
6. Rentals - I like to look at rental pricing vs. payments as another form of comp. Especially if I'm in a low end or first time buyer market. That's competition too.
7. Foreclosures - the data is available so there is no reason to be surprised by an REO popping up next door. Foreclosures are way down, but they are still at levels 5-10 times higher than they were pre-crash.
8. Neighbors - The final comps I like to look at is the neighbors. You know the old saying - buy the worst house in the best neighborhood. How do you know if you don't compare the property you are looking at to the neighborhood. I've made the mistake of buying a house that is overbuilt for the neighborhood. Appraisal wasn't a problem, but finding a buyer was.
Online vs. In Person:
The next thing I'll say about comps is that after you pull them on your computer, get the heck out of the house and go look at them! I don't care who the source is, nothing beats seeing the property in person. Getting a feeling for the traffic, the street, the neighborhood, the street appeal, and if you can get it the floor plan. These are the things buyers will pay attention to. If you want to be good in this business you'll know your markets by personally pounding the pavement, or by having trusted team members doing it for you. Don't rely on pics - you know that they can stretch reality. If you are not willing to do that, then find a super hard working agent to do it for you. Preferably one who tends to have buyer after buyer in their car all day - they'll know what a buyer wants, and what they can pay.