Whilst a full safety assessment for a label might be required, some simple things only need a bit of common sense.
The A300 freighters I was on had a CB for the main deck cargo door that would sometimes pop for no known reason, and at 3am when tired, trying to find it in the electronics bay under floor could cause a delay.
Someone came up with the idea of painting a red ring around the CB and a label saying "This One". Never had a problem finding it after that.
Simple common sense solutions used to be approved by the CAA in a thing called a "Minor Modification".