To get pre-qualified all you have to do is talk to a lender on the phone and give them a few details about yourself and your finances. The lender will then tell you that you are qualified to buy up to a certain amount home. Many will even give you a letter stating so. If you read the letter closely you'll probably find a disclaimer saying that the qualification is based on verbal information provided to the lender and does not constitute loan approval. A sophisticated agent realizes that many problems can surface which will derail a deal. The seller can then expect a longer delay in the successful conclusion of the sale.

If on the other hand you can furnish the seller with a letter saying that you are pre-approved your negotiating position is much stronger. There have been some occasions where my client has had their contract accepted even though a larger offer with a later closing date had been received. If a seller is facing additional mortgage payments that cost is frequently added in to the final sales cost.