My darkroom is a 4' bathroom with no windows. My workbench is the back of the toilet. The light switch is on the outside.
ALWAYS tell the wife and daughter, otherwise more film will be wasted! "I didn't know you were in there, the light's off!"

Using an online metronome for timing during development while tired is an easy way to blank out and lose track of your progress! "Was that 8 or 9 minutes?"

I was out shooting with my new to me 4x5 camera and made what could have been perfect, only I metered for 400 with FP4+ loaded. Using outdated fixer left me a blank and purplish sheet of plastic. It wasn't a total waste, as the underfixed purplish negative can be used to add a touch of contrast when I contact print multigrade with my flash!