How long will it take to install Sage 100 (MAS 90/200)? Every project will be different. The length of time depends on the volume of records to be entered, the changes to be made, the number of modules you’ll be installing and the time available of the staff involved. A small project (GL and AP only) may be completed in a matter of weeks, while a larger project, including inventory and purchase order transactions, may take several months. We'll help you identify a realistic target date, and will work closely with you and your staff to meet that date.