You can have your credit report pulled only so many times within a month before you start to take hits to your credit score.  If you let 5-10 brokers pull your credit you may put yourself in a position where your score is too low to qualify for any rate.

 

This is kind of a catch 22.  Without a credit score and full credit history, you can't find out exactly what you qualify for.  You might want to get your own copy of a credit report complete with your credit scores and send it to people you're shopping around with.  Your scores and credit accounts are important in figuring things such as the DtI (Debt to income ratio) and the LtV (loan to value).  

 

Again, nothing wrong with comparing rates.  The problem is that not everyone in the mortgage industry is honest and has your best interests at heart.  Many brokers will tell you what they think you want to hear.  They'll even send a Good Faith Estimate (which is not final, it is just an estimate) quoting the rate you want to hear.  They'll have you pay $350-$450 for an appraisal and you'll jump through hoops to find out the closing costs and/or rate is higher than you were quoted.

 

They do this because an estimate is just that, an estimate.  It's not final until you get to the closing and sign the closing documents.  Until you request and hold a rate lock in your hand, you have no garauntee that you'll get the rate that was quoted.  But here's the catch, a broker needs a credit report number in order to get you a rate lock and rates are always changing.  Sometimes there's just a little 2-4 hour window when rates drop.  If no one has a complete application on you they can't lock you in at the lower rate when the opportunity strikes.