Well you are actually gambling that rates will stay low or keep going down.
If you lose, you pay more for the life of the loan. If rates go back to the 4% range and you intend on keeping the house for a long time, the extra .125 will be about $125 a year in interest payments per $100,000, gradually decreasing as the balance gets paid down. But on a typical San Diego house, about $12,000 over the life of the loan.
So it is not free money, rather you won a number of bets with banks. That’s great.
The process of doing the refi also results in a credit inquiry and a lot of time and hassle, though that depends on how complicated your finances are and whether you are self employed or not. I am, and it makes the mortgage process more complicated.
I’d need at least $1000 gain before I’d deal with all that, maybe $2000. Personally, if I want to bet rates will go down, there are easier ways of doing so with bond funds and ETFs.
In summary, the cash you picked up from banks doing serial refinances are no more free money than the money I made this year with some good stock investments. In both cases we made money with correct predictions about markets. It wasn’t free because we took on risk to do so.
