Body rust questions

Here's a question for some of the older Jk's and jku's out there in the rust belt.

What's been the first area to go? Where are people seeing rust on these Jks after a couple of years out in the salt unchecked.
Where should I look out for specifically when washing,to avoid salt deposits and buildup of crud.

I try to keep my Jk as clean as possible.. It's a 14 2 door. I've put some skid plates on built by jcr offroad and Rubicon rails as well. I've notice snow, salt, and especially mud buildup on these and wash undercarriage frequently in winter to prevent salt and sand build up.
This is the first area I expect to go, maybe the rockers... I don't know. That's why I'm curious about any rust issues ANYBODY has had. I'll admit I haven't seen much and I tried searching all over the Web. Most posts complain about surface rust noticed after sale. That... I'm not concerned about. I'm talking serious rust. Does anybody have it? Where? How did it happen? More importantly how can I prevent it?

I'm wondering the same thing as I spend a fair bit of time on the beach. Looking at the body construction I'm most worried about the space between the front fender and the rocker. Lots of stuff gets caught in there

I would say for anybody that has drilled or cut on the body or frame and didn't protect those spots.... And whatever you do, DON'T USE SILICONE products to seal unpainted metal. It promotes rust!

My Jeep spent its first four years in CT, then three years in CA, another two years in RI and now a year in AL.

For me the first area was in my rock rails, then the gas tank skid plate. My door hinges also were starting to rust pretty badly. All of these were being eaten from the inside out per say. I also had fairly serious surface rust underneath the Jeep on the lower frame rails. I have since removed the rust and preserved the entire undercarriage twice since buying the Jeep back in 2010. Once right after buying it and then again this past spring.

The gas tank skid plate (at least on a 2007 JKU) doesn't have enough drain holes and the water/salt mixture will just sit in there. I found this out at Uwharrie a year ago when I drug over a rock and felt like it was holding onto to the Jeep. Well the top of the rock basically pushed through that area and I had to force the Jeep off of it. When I looked at it right afterwards I found the "hole" and rotten layers of steel. I simply removed all of the rotten metal and preserved what was left and now I have a big drain hole (about a 4" by 6" oval) in that skid plate.

Hope this helps,
Matt

I get a lot of stuff sitting on top of the skid plates as well as inside the Frame rails and fender wells
So far the action plan is just pressure wash until the water runs Clean, sticking the nozzle into frame rail holes and in behind the wheel wells and in the little cracks between the gas tank and skid.
I specifically attacked the inside of the front fenders with rust check spray before the winter. I used about half a can on those areas alone. Spraying wildly until it ran out down by the pinch seam so I bet I've got a pretty good coating going on in there. I really don't want this thing to rust out... Ever. Even though corrosion warranty is supposed to be very good I don't ever wanna find out. Thanks for the replies.