With some exceptions, once you begin participating in a retirement plan, all of your years of service with the employer maintaining the plan after you reached age 18 must be taken into account to determine whether and the extent to which your accrued benefits are vested, including service you earned before you began to participate in the plan and service you earned before the effective date of ERISA.

However, ERISA does allow plans to disregard certain periods for purposes of determining an employee's vesting service. If you wish further details on what periods of service may be disregarded, see your summary plan description or the plan document to find out what periods are counted in your plan.

When you receive a benefit statement, compare the amount of your accrued benefit with the amount or percentage of your vested benefit to determine its accuracy. If these items are not clear from your benefit statement, ask your plan administrator. The plan administrator may send you a benefit statement each year. If not, you may request a copy. In order to keep track of your vesting service, you may want to keep records of your hire date, the date you began participating in the plan, and the dates of any leaves of absence that could affect your total service.

If the plan's vesting schedule is changed after you have completed at least 3 years of service, you have the right to select the vesting schedule that existed prior to the change for the entire length of your service, rather than the new schedule.

In 2002, changes to the vesting rules speeded up the minimum vesting schedules for employer matching contributions. There are now two alternative minimum vesting schedules that a plan may use.

Under the first minimum vesting schedule ("cliff" vesting), the time period for acquiring a nonforfeitable right in employer matching contributions was shortened from 5 years to 3. This allows employees with 3 years of service to be 100 percent vested in the employer's matching contributions.