It really depends on your financial situation. If you've got the resources to pay off an ARM before the reset, then absolutely you should do that. Why not? If

It really depends on your financial situation. If you've got the resources to pay off an ARM before the reset, then absolutely you should do that. Why not? If you can make the payments on the 30 year easily, then an ARM could be a good bet to save some money, but there's some moderate risk. If you're a bit stretched making a 30 year, then an ARM is probably too risky because a rate increase could push you into default. If you are able to make the payments on the ARM but not the 30 year fixed, then you probably shouldn't buy at all (at least not that property).