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.
live on borrowed time
Fig. to exist only because of good fortune; to live on when death was expected. The doctors told him he was living on borrowed time. You are living on borrowed time, so make the best of it.
be/live on borrowed ˈtime
1 (of a person who is seriously ill) live longer than the doctors expected: The doctors say he’s living on borrowed time.
2 be doing something that other people are likely to soon stop you from doing: The government is on borrowed time (= they are not likely to be in power for long).