The time when one must pay up or face the consequences; originally referred to the time to pay land tax.
不正が発覚して、ついに年貢の納め時が来た。
The fraud was uncovered, and finally the time to pay the piper has come.
会社の業績不振が続き、社長にとって年貢の納め時かもしれない。
With continued poor performance, it might be the CEO's time to be held accountable.