It depends on the number of pages to be converted. We have done almost 35 IETMs of various levels. As per our experience to make Level 3/Class 3 IETM having 5000 pages, it takes around 30 days. For documents 10,000 to 20,000 it takes around 60 days. Major hindrance that we face is availability of final documents from OEM. We had this experience several times that OEMs have to collect documents from many sources and number of versions are available for each document. OEMs usually focus on actual equipment but not on documentation of equipment. Collecting final approved files from OEM is the biggest challenge in IETM development. If all the final approved documents are in place, it takes standard time as mentioned above.