make-or-break
adjective
ukus(also make or break)used to describe a decision, event, or period of time that is very important because it can make something succeed or fail completely:
Christmas is often a make-or-break time for smaller retailers.
A spokesman for the union described the forthcoming pay talks as "make or break".
a make-or-break decision/deal/issue
make-or-break meetings/talks/negotiations
Each interview that you attend is a make-or-break situation.