In general, vacation accrues over time as an employee works. For example, if a vacation policy gives an employee ten days of vacation each year, he or she will accrue five days of vacation after working for six months.
Employers can designate a waiting period at the beginning of employment before vacation starts to accrue, though. The waiting period often correlates with the 90-day introductory period, but can be as long as the first year of employment.
Employers can also give vacation to certain groups of employees but not others, as long as they don't discriminate based on a protected characteristic, such as race or gender. For example, employers may give vacation only to full-time employees or only to managers.
David Payab, Esq. from The Law Offices of Payab & Associates can be reached @ (818) 918-5522 or by visiting http://payablaw.com