ISTA test protocols should be repeated periodically or as necessary to maintain the quality characteristics of the packaged product on arrival. In addition, tests must be repeated whenever there is a change in the product, the package, or the process. Some changes are not included in this requirement, but only if the change is not associated with potential performance in any way. Changes in the product can include changes in:

• Design (configuration, components, accessories, etc.)

• Size / weight (dimensions, shape, mass, center of gravity, etc.)

• Materials (type, construction, fabrication, gage, etc.)

Changes in the package can include changes in:

• Configuration (individual package or unit load, container type and sub-type, style, design, interior packaging, etc.)

• Size / weight (dimensions, shape, mass, caliper, gage etc.)

• Materials (corrugated, plastic, metal, glass, etc.)

• Components (closures, labels, straps, pallets, skids, wraps, etc.)

Changes in the process can include changes in: • Manufacturing / assembly (vendor, location, automation, etc.)

• Filling (equipment, speed, automation, etc.)

• Distribution system (parcel delivery, LTL, intermodal, etc.)

When there is any doubt as to whether a change will potentially affect performance, retesting should be done. Determining when retesting is required may involve knowing and tracking specification details of both the package and the product, such as new or changed components, materials, interior packaging, closure methods, etc.