If you noticed on your closing disclosure form that your closing costs have changed from your initial loan estimate, you can ask your lender why. It's not uncommon for certain costs to increase a bit between when you first apply for the mortgage and your closing. But some costs, including fees you pay to the lender, fees you're not allowed to shop for (such as the appraisal fee), and transfer taxes should not increase at all unless you've had a substantial change in circumstances.