You are driving car, running with seventy miles speed.. it is smashed accidently. But you are alive then you have to change your car. Similarly, we can drive this machine called the body for so many years; then it becomes old and we have to change it for another machine. This is the process of birth and death.
The kitten is feeling pleasure: "Oh, my mother is carrying me."
The deer is feeling death: "Oh, now I'm going to die."
So, although both devotees and nondevotees die, there is a diffrence of feeling at the time of death.
The unsuspecting fish, who knew nothing but a life in the river, went about its routine like any other day, but in an instant was ripped out of its reality to meet with death.
If at the time of death one can remember Krishna, one’s life is successful.
Srimad Bhagavatam 10.1.5-7,
If one doesn't practice remembering Krishna while one is struggling for existence, then it will not be possible for one to remember Krishna at the time of death.