You ever talk to someone in another field and they start talking about this terahertz range or this cm^(-1) photon, and you start quickly try to convert it your gold ol' trusty units? You can drop your field and its unit of choice.
When I was doing OLED work, it was almost always wavelength, and sometimes eV. My lovely green OLEDs would shine at 550 nm, or \~2.3 eV. #science source