What’s all this APR stuff they tell me about at settlement? Why is it or is it important?
Could be but it is designed to show you the cost of your credit over the term of your loan. In most likelihood you won’t be in your home for more than 7 years. The APR takes into consideration the loan discount points in your loan, the term, rate if it’s adjustable and other factors.
What you may want to focus on is what’s it costing me as a percentage of my principal balance. Negotiate a good loan, read the fine print, use a reputable lender and make sure you have a competitive rate. You are smart, you can do this.

