In my opinion, it would depend on the company. Original validation would expire because changes are made within equipment and those changes need to be validated to assure that the equipment will produce accurate results. It would be a on a case to case bases. For example, a mass spec used in a major product would not need to be re-validated. However, if a machine has a part that has been modified or an additional part has been added, than it would need re-validation. Also, at some time your validation will expire because FDA doesn’t approve things for life. New discoveries are made, consumer reports, and other factors will cause re-validation of equipment.