Some real estate agents or sellers will gladly know that you have an agreement in principle before looking at a property or making an offer, as this gives them the certainty that you can afford it and that it does not affect the sale. You do not need to go through the entire application process to get an agreement in principle. This will come later if you have accepted an offer for real estate. Even if it is not a complete mortgage application, you must still provide information to reach an agreement in principle. If you re-perform, this information will be less necessary, so you would submit an agreement in principle once you have chosen a lender and a product. A decision in principle is not a guarantee.