Inclusion Criteria:  Full time National University of Singapore students (undergraduate and postgraduate) Singapore Citizen or Permanent Resident; Has a Singapore registered mobile number• Owns a mobile phone with operating system that is compatible with the study app (iOS 10 or Android 7 and above); Able to make the upfront deposit of $20 and able to set up the Direct Debit Authorization (DDA) for possible deductions by HPB; Able to understand the study procedure during the informed consent taking process.  Exclusion Criteria:  Students who will be overseas for more than 6 weeks per trip during the study period (e.g. involved in overseas exchange/internship programmes or stationed overseas) or travelling frequently; Students who are not able to set up the DDA via online method will be excluded; Students who has worked in a full-time position for more than a year previously; Pregnant women will be excluded only at the point of recruitment.