It can be used all by its lonesome:
[woman is late for a date with her boyfriend]
[boyfriend, annoyed]: Era ora!
Ci hanno dato l'aumento!
Era ora!
They gave us a raise!
'bout time!
When it is in a sentence it is followed by the imperfect subjunctive (where in English you have the past.)
Era ora che mio zio mi prestasse dei soldi.
It was about time my uncle lent me some money.
Era ora che vincessero i Red Sox.
'bout time the Red Sox won.
