Customer called us out because their door was stopping halfway when opening. When I did get on site, it was operating normally as it should, but I was able to diagnose the issue as a bad limit switch on an opener that was already 16 years old out of a life expectancy of 15 to 20 years. I recommended replacement of the opener, customer authorized the replacement. Once I got the opener replaced, the door had opened and closed smoothly and quietly with the new openerthat was installed.