The action of one party, person or product being replaced by another that has become obsolete, incapacitated, retired or deceased. Ideally, a successor will fill the role of its predecessor, being fully compatible with all other entities in place and perfectly functional without any interruption in service.

Since the Sarbanes-Oxley Act, planning for succession of a executive officer in a corporation has become a very important issue in the field of corporate governance. Ensuring that, in the event of a problem with one employee, a company will continue to function adequately creates tremendous value for shareholders.

Family succession is the passing of one person's assets and role in the family onto an heir.

With the increasing pace of technological change, when new products replace old ones, it is important those new ones can fill the role of the old products without interruption in service and without the need to replace other functional elements of a network of products.