crunch time

1. a period of intense pressure; a critical situation.

   It's crunch time for high-tech companies.

Word History and Origins

Origin of crunch time¹

1975–80

Idioms and Phrases

A period when pressure to succeed is great, often toward the end of an undertaking. For example, It's crunch time—we only have two more days to finish. This term employs crunch in the sense of “a critical situation or test.” [Slang; 1970s]