live on borrowed time
To live or exist in a temporary and/or tenuous position, which may come to an end suddenly and abruptly. Accidents and disease can strike so unexpectedly that it feels like we're all living on borrowed time.
on borrowed time, live
Outlive reasonable expectations, as in Our twenty-year-old car is living on borrowed time, or The vet said our dog is living on borrowed time. This expression alludes to time borrowed from death. [Late 1800s]