Your agreement in principle has a duration of about 30 to 90 days depending on the lender. If your circumstances or credit history change during this period (for example. B if you miss a credit card payment), the validity of your AIP changes. An Agreement-in-Principle (AIP) is the next step after having a PMI. Get a mortgage in principle from Trussle for free in a few minutes. If you`re applying for a mortgage in principle, it takes a few seconds for the system to compare your data to its underwriting information to tell you how much you can borrow. You can also see how much typical monthly repayments would be and how they would change if other conditions were offered to you, as well as other fees such as attorney fees and stamp duty. .