This ^^^^^^^^^^^^^^^, always.
Measure it or take it to someone who can.
Not in a light, but I've had a similar issue on the past (the unit was still working, however) and measuring it showed my visual skills to be out be several magnitudes - not all colours change the same way).
NB. I replaced mine with a higher disipation resistor and whilst still working many years later I notice it will need a still larger replacement in due course, so if going from, say, 2W see if you can squeeze a 5W in the space.