I bought two identical machines, one year apart. First one the motor lasted one year, burned up, filled the room with stinky smoke. The other machine is still going strong after five years. The motor costs about half as much as the machine and took about three months to get.
I think machines are like cars, some get to 3 thousand miles and some maybe get to 1 thousand miles. Just the luck of the draw. I have often wondered how cost effective is making quilts with tiny scrap pieces. When electric, sewing machine life and time is all factored in.