How to avoid developing common code again and again

This can be a common occurrence if you have one or multiple HL7 programmers.  If you have multiple HL7 programmers, this problem can be compounded exponentially if there isn't a process in place to address it. Look for common functionality that can be used across multiple interfaces, and then have a process in place where it can be develop once and then stored in a designated area that all programmers know about.  A real life situation is filter transaction by location.  Allow the script or program to pass the location(s) as a parameter so that it can be flexible across various interfaces.  This type of structure will foster an environment of working smarter not harder!