The answer is to follow for equipment a life-cycle approach as described in FDA's latest Process Validation guidance.  There needs to be rigorous change control, periodic calibration and preventive maintenance programs in place for each piece of equipment.  Beyond that the performance of the equipment is trended directly (for HVAC, WFI and other routinely monitored utility systems) or indirectly through trending of the products / materials manufactured in them (as Stage 3 in the PV guidance requires).  If these are done rigorously there is no need for periodic re-qualification because the equipment should remain in a qualified state at all times, in the same fashion that a Stage 3 product remains in a validated state. Exceptions could be considered above and beyond this for critical systems such as those used for sterilization,  This is common in conjunction with the regulatory expectations for annual re-validation of sterilization which has not been removed despite the presence of the PV guidance which suggests otherwise.  


2015 Agalloco & Associates Training Schedule - Both courses in Princeton, NJ
October 19-21 - Sterilization: Principles & Validation
October 22-23 - Aseptic Processing: A Comprehensive Review
Details at