Why clean your reels?

I have a Penn Pursuit II and rinse it in fresh water after every trip for the last 3-4 years.  While I've never taken it apart, the last trip out the anti-reverse just stopped working.  I ended up disassembling it all and saw a lot more salt build up than I would have expected.  After cleaning it all up it was nice to see how the internals functioned, however I never could get the anti-reverse to work.  It looks like it's just a nut that locks, but ohh well.  Even if I got it working the whole reel isn't as smooth as it used to be.  Fortunately Penn is discontinuing the model and I picked up a backup for $30 

It also seems like I need to be doing comprehensive tear downs anytime the reel takes a dunk in the future 

Definitely good to keep your reels cleaned and greased. If you dunk your reels from time to time like I do, it's a must.

I know of people that soak their reels in a bucket of freshwater after it's been in the salt, although I hear mixed things about it.

Forcing fresh water into the internals of your reels under pressure is not good

I recently sent a rod and reel to the bottom of Tomales Bay.
I managed to snag it and recover the gear. When I broke down the reel (Penn 550ssg) I was shocked to see a fair amount of sand that got inside. I tore it down, degreased, cleaned and lube it. Now it works better than ever.
Go figure.
 You tube is great for reel cleaning videos.
I bought a kit from Abu Garcia and am happy with it.
An ounce of prevention,  right!

Definitely good to keep your reels cleaned and greased. If you dunk your reels from time to time like I do, it's a must.

I know of people that soak their reels in a bucket of freshwater after it's been in the salt, although I hear mixed things about it.

My brother does this. He actually soaks it in warm watee overnight from time to time. Never really asked him why. What is are the cons to soaking in fresh water?

Forcing fresh water into the internals of your reels under pressure is not good

After being on (and sometime in) the saltwater, I always spray my reels with a hose. As long as you keep the pressure down so that you don't wash out the grease, it works well.