When they are older and showing signs of dementia, usually a family member responsible for care will enforce the time limits.
The factors that affect your health that you can control:
diet
exercise/being active
hygiene
mindset/attitude
lifestyle
medical care
etc
factors that are outside of your control:
genetics
environment (although it is in the hands of us humans, but a person alone can’t do much)
society/culture
Access to mass media and emerging technologies