I have the Hot Wire Foam Factory, it's got lots of miles on it. I've replaced the wire once, and I push it with a train transformer rather than the anemic wall wart that came with it, that allows me to adjust the cutting speed as well as for the material I'm cutting. I have a roll of nichrome wire that I got for when the spare wires died, but I've yet to use it, and I still have two of the three nichrome wires that came with it. You must really be pushing the power to smoke them within a week!