Crunch time

[Tdol]

You can find the definition of this idiom here.

[RonBee]

It's crunch time. It's now or never.

[blouen]

It´s crunch time, I need to cast my vote.

[candy-man]

a crucial decision to be made.

[Marixi]

This one is new to me. Thank you.
I also found "when/if it comes to the crunch" used to say what someone will do when a difficult decision has to be made.

[Lynxear]

It's crunch time. It's now or never.

In my experience it means more than just "It's now or never"

The person who says this idiom probably has had this problem for some time. He has postponed the decision to the last minute. He may succeed or he may fail as the outcome of his action is probably uncertain. He has finally sucked up his courage as he realizes that he must do something. So, perhaps against his better judgment, he is going to do something risky since he risks losing more by doing nothing.

[kofling]

a vital decision must be taken

[mafioso]

crunch time is the sputnik moment, da moment of truth,da reckoning...
no matter.crunch time doesn't sound sophisticated,it's too trashy and simplistic.

[banderas]

according to wikipedia:

Crunch time refers to the period of time immediately before a project (or other timetabled item) is due to be done. It is typical for crunch time to occur between the next-to-last scheduled milestone and the final project completion date. Then, its projected completion timeline is either a miss, or a hit.
In basketball, the term crunch time is applied to the last few minutes of play in the fourth quarter. Here, both teams gear up to secure the game with fierce play, effectively ending the endurance match of the first, second and third quarters. The term was invented in New Zealand in 1984 as a combination of the two phrases show-time and when it comes to the crunch

Question to stuartnz: have you heard about it?

[susiedqq]

Very simply: IT'S NOW TIME TO GET DOWN TO BUSINESS!!