It does depend on yrs of service.
For every week of vay cay you earn, you can bank up to double before losing it.
If you earn 2 weeks/yr (5-10 yrs service), you can save up to 4 weeks at which point it stops accruing.
Same with personal holidays.
Say you get 18 hrs PH, you can save 36.
At 15+ yrs, she prolly earns 3 wks/yr (120 hrs vay cay) so she could save up to 240 before accrual stops.