The life time of a spout in 993 is longer than a fused cast inserted spout. A fused cast inserted spout usually increases the life of a spout by 100%. We have had a number of 993 spouts in service for over 2 years. Things that effect the life of any refractory expendable is the pull rate, glass temperature, glass composition, glass colour and installation procedure. It is therefore difficult to say with any certainty how long a spout will last unless the customer is willing to try one so they can compare to a normal 315 spout. Fused cast inserted spouts take around 16 hours to change, glass to glass. 993 spouts taken the same time to change but are less prone to thermal shock. I visited a customer last week who changed a 993 spout in 6 hours and it did not crack. However, we do not recommend changing a 993 spout so quickly. I hope this information is helpful but please get back to me if further clarification is required.