After a bit more thought, the "technical" comment probably refers to the bottom seal. In order to change that seal you must remove the gear box and that can be a pain. However, it's that seal which is more likely to be the culprit in a catastrophe. It's easier to have an undetected oil leak because of the center pulley and grass clippings and debris obstructing your view.
I wouldn't change the seals unless there was a reason UNLESS you know you won't check them periodically. If it starts looking oily and goopy around the bottom of the gear box check those seals!
