Quote Originally Posted by mjdehlin View Post
If it's in good shape I'd be hesitant to do anything to it at all in fear of "upsetting the balance" that has kept it in good shape so far.
Bingo, this is my philosophy as well. You never know how long it's going to last without any treatments, and there are plenty of D's around with the original, uncracked dashboard to show that they can last over 30 years. Mine sat in the Vegas heat for about a decade, so much so that the passenger A-pilliar warped under the heat. The previous owner used duct tape to reattach it, but the backing came off due to heat issues as well, so it became very visible. Yet there isn't a single crack in any of the vinyl, whether dashboard, binnacle, or glovebox cover. It's pretty much flawless, and as far as I can tell, it is the original, untouched vinyl. If mine's lasted 30 years in Las Vegas heat, who knows how much longer it'll last like this.

And even if it does crack and I have to get it replaced soon, the cost to recover the vinyl is well worth the 30+ year lifespan. Not worth the time or effort to use anything to protect it in my book, especially since it's mostly unknown if these products reduce or extend the vinyl's lifespan.