Getting pre approved for a home loan just lets you know how much the bank is willing to let you borrow to buy the home. It lets you know what price range of home you can look at. Next, once you pick the home, the home must meet certain standards and be acceptable as the collateral for the loan the bank is about to give you. The loan can't be approved if the house is not acceptable and without an appraisal and an inspection, there is no way to know if the house will pass. It actually helps protect you from things you may not have noticed while looking at the home. Bad foundations and termite damage aren't always obvious to the untrained eye, but the inspector will catch things like that and save you and the bank a big headache later on. And the appraiser helps certify that the home is actually valued at what the seller is asking. The appraiser doesn't just look at the house you are purchasing, they rate the over all neighborhood and the value of the homes near your home. It is true that a bad home, or a home left uncared for can make the value of the homes around it go down. An appraiser would catch issues like that. If the appraiser found the value of the home to be less than the asking price, you could use that to try to purchase the home at the lower price, and maybe get the house you want for less than what you think you are going to have to pay right now. There is always a slight risk of being denied because of a problem with the home, but most of the time, the seller has usually done the right steps to make sure their home can sell, especially if they are using a realtor. After all, they want out of the home because it isn't right for them anymore, so they want it to pass these inspections.