The Buddha recommended that every person should remember every single day that we are not here forever. It is a guest performance, which can be finished any time. We don't know when; we have no idea. We always think that we may have seventy-five or eighty years, but who knows?
If we remember our vulnerability every single day, our lives will be imbued with the understanding that each moment counts and we will not be so concerned with the future. Now is the time to grow on the spiritual path. If we remember that, we will also have a different relationship to the people around us. They too can die at any moment, and we certainly wouldn't like that to happen at a time when we are not loving towards them.
When we remember that, our practice connects to this moment... We need to act now. We can only watch this one breath, not the next one.
~ Ayya Khema, When the Iron Eagle Flies