Forget all the so-called rules of thumb. The key to a refinance is saving mortgage interest while keeping an eye on closing costs, and at same time anticipating how long you’ll own the house.
Note that there is really no such thing as no-closing, or no-fee, or zero-closing-cost loans. In fact, that’s rally a dubious claim, and with good reason: There are closing costs! Instead of your paying them at closing, they’re buried in your new, higher rate. You pay every month.
