Passage of time has no effect on the validity of a Will. So, even though your family needs likely have changed over the past 10 or 20 years, that long ago prepared Will is still controlling. Tax laws, and laws concerning Wills might have changed as well.
To be sure your estate plan is up to date, it should be reviewed by you annually. Have there been major life change such as a death in the family, the birth or adoption of a child, a divorce or marriage, or a significant change in assets.