I use my 175 in salt water several times per year. Here is how I keep it in shape.
1. at least once per year, get under the console and spray everything down with "Boshield", this puts a protective coating on all the exposed terminal ends. Also spray down inside the bow and stern light sockets.
2. Good coat of wax on the boat, an extra good coat of wax on the swim ladder.
3. Galvanized trailer only.
4. Good soap and water clean up after each use in salt water.
5. Good fresh water flush of the motor. I take mine out in the Titusville Fl area. On the way home I stop by a local lake, back down the ramp and if not busy just run the motor for awhile. If the ramp is busy, I launch and run around a little.
Mine is a 2001 model and I have not had any problems.