I actually learned about OE's before I learned about SID. Bear has SID (I'm borderline) and both boys, as well as myself, have OE's. The way I drew the line was when it is a constant disruption to everyday life it is probably more along the lines of a disorder than simply and OE. I've actually read something pretty much exactly along those lines in one of the sensory processing books. They said something like, "Everyone has times when they have difficulty with sensory processing, it's when it becomes a complication to everyday life that it becomes a disorder." I'd say it's sort of a spectrum type thing.