one bite at the apple

1. law A single opportunity to litigate a civil case against another party. (Once a case has been resolved by a judge, a plaintiff or prosecutor cannot pursue the same case against the same party again in the future.) Even though you've got new information proving the other party is responsible, I doubt you'll be able to bring charges against them again. The judge already ruled that they were not negligent, and you only get one bite at the apple.

2. By extension, a single chance to try or accomplish something. The new administration only has one bite at the apple for this peace treaty, so they had better make sure that they get it right. I'm getting old. I doubt I'll be able to reach the Olympics again, so this is my one bite at the apple, as far as I see it.