I have a 30-year mortgage at 4%, on which I have about $485K left. Monthly P&I is about $2,350. Just a few days ago I contacted my mortgage broker to inquire and he ran the numbers. At 3.25%, which is totally within reach, I'll save about $250 per month, so $3K per year, which I think is absolutely worth it. There are "voices" predicting even lower mortgage rates within this year, and at 3%, we are at a historic low, and it would be crazy not to take advantage of this . . . unless you only have a few years left to pay it off.