Mine had 220 hours on it when I bought it and was making noises, louder when turning.  I replaced the u-joints somewhere between 250-270 hours and that quieted it down about 90%.  I haven't done the gimbal bearing yet.  I grease the gimbal bearing before every trip.  I had the outdrive removed a few summers ago to remove a burnt flapper from the port side exhaust and the bellows was still in good shape.  I will replace the bellows and the gimbal bearing at the beginning of next season.  If only doing the u-joints, it's a fairly easy intuitive task if you have a cradle or other make-shift support.  Here's one I welded up with some scrap:

