5 years to be vested means when you reach retirement age, you will be qualified to receive something.
It also depends on who is managing the pension plan which varies by region.
My plan is handled by the union.
And their plan is based on the number of hours worked per year.
1800 hours gets one a full year's pension credit.
They have a sliding scale that cover all hours under 1800. ( 0-250 hrs = zero credit )