Smartphones have become thoroughly widespread even among older people. In January, the NTT DOCOMO Mobile Society Research Institute surveyed 1,300 people aged 60 to 84, finding that smartphone ownership was 95 percent among those in their sixties, 86 percent among those in their seventies, and 69 percent even among those aged 80 to 84. Smartphone apps are convenient, but people may forget passwords they have set, and leaving passwords stored on their phone