Having a letter of pre approval is an invaluable tool.
The letter shows that you have been in touch with a lender. It also shows that you are qualified to get a loan. At least there is a professional who feels good about your chances of getting through the loan process.
The seller is considering not only the offer you have made, but they are faced with whether they need to take their active property off the market to allow you to do inspections etc.
Having a letter from a relatively unbiased person is like having an authority put a stamp of approval on you.
It is our feeling that no seller should consider an offer unless it comes with a pre approval letter.
Think about it. If you were the seller, wouldn't having a lender letter improve your comfort level?