For areas such as where I live it is imperative that you protect your Jeep Wrangler or any car really with an undercoating product of some sort. I decided to use a product made by Rustoleum. It is a rattle-can solution that anybody can do. The product is made to protect the underside of your auto. It is not very resilient anywhere else since the sun will break down the product.
Be sure to get all the areas you have access to. The underneath part of a vehicle won't really rust much, but you will need to be sure to get areas in the back well.
Some areas are going to be impossible to access such as that part underneath the fenders in the front where the rust can show up on the top. For areas like that you can use something called Fluid Film. Make sure to cover the back of your tail lights. This area can get rust as well. Another area hard to reach on the Jeep Wrangler is inside the frame rail.
Be careful to make sure your surfaces are well prepared. The better they are prepared the better the results will be.
I would be sure to use Fluid Film in the suspension areas. This is important to allow the future removal of parts that break or otherwise need replacing. If parts can be prevented from getting rusted to each other it makes it a whole lot easier to remove. I would use this product in other areas as well where you have moving parts or parts exposed to the elements that could get seized.
I just got a TSB letter in the mail today about the ODB light in my Jeep Wrangler.