Fit Testing should be reviewed on a case by case basis. Here are some of those instances: have facial features changed due to substantial dental work, weight gain/lost, scarring, facial abnormalities due to accidents, facial surgery undertaken. It should also be reviewed if the mask model type has been exchanged to an alternative make / model number.
Be mindful of irregular shaped temples, cheek bones, angular faces as these may not conform to your chosen mask. The critical nature of RPE being sized, fitted and donned correctly will allow a confident seal around the face.