While attorneys do our best to draft wills that are durable, and will reflect your wishes in a variety of scenarios (related to who may or may not survive you, who will serve as executor, etc.), your will may need to be updated when 1) your wishes change, 2) your situation changes, or 3) the law changes.
In short - yes. Some people think an estate plan means an intricate series of intricate trusts and closely held corporations used for tax avoidance. While that can be part of an estate plan, that's not what most people need - if you and your spouse's total assets are worth less than $10.9 (2016) million, you won't need anything like that to avoid paying estate taxes.
For most people, an estate plan consists of 3 documents - a will, a financial power of attorney, and an advance directive.