HALT (Highly Accelerated Limit Test) technique is one of the accelerated stress testing methods. It is a process to discover the design defects and/or weaknesses in products and devices quickly by applying far harsher loads to them. It is generally understood that HALT is a technique not for predicting the product life but for grasping design margins of products. The effectiveness of this technique, however, has never been clearly discussed or demonstrated based on data obtained through actual tests. So, we introduce the assessment results which have been made on the technique by evaluating over 300 items, accompanied some evaluation results and effects. We also make some suggestion on an original method to cover a number of degrading factors, in addition to the stresses of temperature and vibration which ordinary HALT chambers can usually provide.