Question about Chi flat irons !?

Why do chi's brake so easy i had 2 chi flat irons in the last 10 months and they both broke out of no were for no reason my frist one i had for 8 months broke for not reason and then i bought a new one pink dazzle and that one i had for two month brokw out of no were it was on when i did my hair then i noticed it was gettin colder and it was off so o tryed to turn it off the on didnt work i tryed it in different outlits nothing? then took it apart to see if there was any lose wires there was none or see if anything was blown but nothing seemed all good and my sisters was the same thing broke out of nowere and we got ours at salons to soo whydo they brake so easly?