Fannie's new lending initiative, which took effect on June 1, can make the phrase "full loan approval" about as meaningful as the undying declaration of love from an inebriated guy you met in a bar an hour ago. Until the fat lady sings (and hands you the keys to your new home), loan approval cannot be counted on--no matter what the piece of paper in your hand says or the nice mortgage agent on the phone tells you.

Why? Because your lender will likely double-check your credit report immediately before closing your mortgage. Any changes for the worse can result in repricing your loan, tossing it back into underwriting, or even outright denial of your loan.

Mortgage Lenders on the Hook

The reason lenders will be rechecking your credit just before closing is that Fannie Mae wants lenders to make sure that your credit profile is not changed while the loan is being processed and your new home is in escrow. If the profile does change and the lender doesn't catch it, Fannie Mae could refuse to buy your loan--at best messing with the lender's cash flow and at worst sticking it with a fat loss.

To make sure you loan can pass muster with Fannie Mae, your lender will look for evidence that any of these things has occurred:

• You applied for new credit
• You increased debt
• You financed major new purchases, like cars or furniture

If your credit is pulled and there are material changes, it could cost you time or even your new home mortgage approval.

3 New Home Tips: What Can Happen When Your Credit Is Pulled Twice

Here's what mortgage lenders look for, what can happen, and what you should do to avoid it.

1. An increase in debt: If you have increased your debt, either by running up balances (debt that happens in Vegas doesn't stay in Vegas) or financing new major purchases (suck it up and drive that Pinto another month; if it hasn't killed you by now...), your file goes back into underwriting, and your debt-to-income ratio is recalculated. If your debts are too high, you lose your loan approval.

Avoid this by waiting until after you close on your new home purchase before shopping for furniture, big appliances, or autos.

2. A drop in your credit score: Credit score thresholds change every 20 points. Someone with a 640 score pays considerably more than a borrower with a 660 score. If your score drops from 659 to 640, you stay within the same tier, so there is no effect. But if you drop from 660 to 659 (yes, that's one freaking point, folks), you drop into a lower level, incurring an additional loan-level pricing adjustment (LLPA).

Head this off by avoiding applying for additional credit, which generates an inquiry and can drop your score, by paying your bills on time, and by keeping your balances low--increasing your debt load could cause your score to drop.

3. Inquiries that could result in the extension of additional credit: Inquiries on your credit report are indicative of possible new accounts (undisclosed debt), and underwriters will have to pull your loan (possibly delaying your closing) and ascertain what accounts have or have not been opened as the result of those inquiries. If you have to have something silly, right this minute, pay cash already! Or borrow from your mom.

Better policing of mortgage applications and heading off questionable approvals before they become foreclosures will likely ultimately help keep the cost of mortgage financing down by minimizing future losses. Don't let thoughtless actions on your part cause your new home purchase to fall apart, even though your loan is "approved."