I ve done it both on 50 amp and 100amp. Pretty straightforward. Disconnect the end of the cable, remove the stop switch ring, pull the cord out then feed in the new one. How hard is the job depends on how much access you have and how big you are
How small you are. Some of the tubs and connecting points can be deep in the depths of the never seen before.
Tie a pull cord to one of the leads on the old cable, it makes pulling the new cable in to the cable wheel much easier on some boats