Building with treated wood and the idea that this project will last forever because of the wood you used is not necessarily true. Over the years I have seen contractors and homeowners use treated wood for projects like building decks with this idea in mind.
I just met with a homeowner that was asking me about vinyl fencing. The homeowner approached me with some facts about vinyl fencing. She started to explain to me how long a vinyl fence would last verses a wood fence. I reminded her that the vinyl posts usually slip over metal or wood building materials.
She proceeded to inform me that treated wood will last a lot longer than Vinyl Decking Guys building a wooden fence. It took me a while to change her mind and reprogram her with a few picture this from my website. I know this is hard to imagine but wood rots and steel rust.
All you end up with is a vinyl fence that is in pretty good shape if taken care of properly laying down in your yard with broken or rusted fence posts.