Tibetan Buddhists and many indigenous people see the wisdom in reminding themselves daily that ‘one day this body will be a corpse’. In the Christian tradition too there used to be a practise of wearing a ‘memento mori’ around the neck.
Mirrors and water are symbols for that which is passing away – the reflection of the soul – a reminder of change. Some cultures cover up mirrors when someone dies in case the soul flies into the mirror and gets stuck.