Without trying to start something, but you folks don't live in Ohio or one of the surrounding states that compromise the "rust belt". Unless you garage the vehicle in reference during the winter, the salt that is put on the roads during the winter will absolutely eat a vehicle up. I had my truck Ziebarted when new. Each summer I have to get under it, scrape any loose undercoating off, kill the rust with Ospho (phosphoric acid) touch up with Rustoleum and have it re-undercoated. After 6 years my truck is in good shape and will easily last 20 yrs or more, AS LONG AS I STAY AT IT. It is an 04.5. I have looked at trucks that are 2 to 4 yearsnewer and the frames are all rusty, the floorpans are starting to show areas of corrosion etc. The factory undercoating on the frames will start to allow penetration at the points where there are rivets, access holes etc.
In Ohio, if you don't rustproof, you can almost guarantee you will have a rusted through spot in 7 or 8 years somewhere on the body.
The 1991 K2500 that is in the garage being restored was not undercoated as I didn't have the money at the time due to a divorce and being a single dad raising the kids. Needless to say, I have had to have rockers, cab corners, 1 door, new inner and outer fenders and a new bed for it. Yes it was a little money, but since it was paid for, I will have essentially a new truck when done. It has some sentimental value and is a 8600 GVW 4x4 with a 454 engine in it.
If you don't live in the rust belt, then undercoating is debatable. But for us here, if you intend to have a nice vehicle that doesn't have holes eaten through it then you have to go to a place such as Ziebart and also work at it yourself continually.
If you read the WTB (want to buy) ads, lots of people will out and out say no northern vehicles.
that is just my experience for what it is worth.
psssttt drcook = David R, not Dr. but thanks for the compliment. Most folks just call me Dave.
2004.5 Chevy Duramax crew cab 4x4
2010 Crossroads Cruiser 30QBX
1991 K2500 4x4 being restored