I live where they salt roads in the winter. I get mine undercoated every year and internally sprayed ever other year. The place I go to used no drip.
When I was under my Pat putting on the trailer hitch, I noticed lots of areas where rust would start. Even if there was no road salt.
So in my opinion I'd say get it done no mater where u live.

 

I just buy cans of antirust oil and spray the undercarriage myself.I do it in the summer so the oily surface gets enveloped in dust just like a wienerschnitzel gets covered in bread crumbs,same idea and it works.

 

I am trying to figure out what antirust oil is - but hey automotive stores sell spray undercoating too.

 

I think undercoating is unecessary on modern cars. Most manufacturers use galvanized body panels for rustproofing, so I see this as an unneccesary expense that the dealer like to sell to you.

And from my experience, once the undercoating dries out, it tends to shrink away from the body panels and trap water against the metal.

Since the Patriot has a 100,000 mile warranty against body rustthrough, I don't think you'll have a problem without. Just run it through a carwash that has an undercarriage spray every few weeks to keep the salt and crud off the underside.

 

In Canada, I believe we have a 3 year warranty on rust through.
I and my family drive our vehicles till they are not worth repairing. Usually 15 plus years.
None of our vehicles have ever rusted through and this is due to having No Drip oil spraying done as mentioned in my above post.
If I didn't live in a area that used salt on the roads. I'd still get it done when new.