I just checked. Actual time used on the van is 11 months and 5000 miles. 
I am of course convened, as I've installed probably a dozen of these boots in that time on other vans (and other places on this van). 

-craig

On Mar 22, 2013, at 3:05 PM, Stuart MacMillan <stuartmacm@GMAIL.COM> wrote:

> It's an elasticity issue.  Those folds "fold" every revolution, isn't that
> something like 800,000 times every 1000 miles?  It takes a top quality
> rubber to hold up to this constant flexing.
> 
> 
> 
> Stuart
> 
> 
> 
> From: kenwilfy@gmail.com [mailto:kenwilfy@gmail.com] On Behalf Of kenneth
> wilford (Van-Again)
> Sent: Friday, March 22, 2013 11:35 AM
> To: Stuart MacMillan
> Cc: Vanagon List
> Subject: Re: Cv boots cracking
> 
> 
> 
> We used to be able to get the GKN/Lobro aftermarket boots for the rears and
> when we did, you could look around the edge and see the VW/Audi logo that
> was just under the edge of the metal base of the boot.  When I did this
> occasionally I would get someone who had a similar problem as Craig.  They
> would tell me that they installed the boots and they only lasted a couple of
> years.  Then other folks would never really have an issue with them.  I am
> not sure if there is an installation issue that could cause the boots to
> prematurely fail?  I wouldn't think they would dry rot and crack unless the
> rubber itself had just failed because of the quality of it, but I am not a
> rubber expert.  Any one have an idea of why this would happen to some and
> not happen to others?  Right now we have either Rein (which I haven't been
> getting any complaint on) or Meyle.  Of the two I would rather use the Rein
> brand as they seem to be a higher quality brand and are made in Italy.  The
> Meyle brand is usually made in China or India.
> 
> 
> 
> Ken Wilford
> 
> John 3:16
> 
> www.vanagain.com
> 
> 
> 
> On Fri, Mar 22, 2013 at 12:56 PM, Stuart MacMillan <stuartmacm@gmail.com>
> wrote:
> 
> The OEM dealer boots are EDPM rubber (at least they used to be) and worth
> the money.  My '84's boots were still good when I sold it in 2006 after 200k
> miles, and I replace the joints once (not the boots). Lucky for me, my "new"
> '85 still has the original boots and they are fine after 145K.
> 
> I don't know what some of the aftermarket boots are made of, and there is
> probably no way to tell for sure.
> 
> It's too bad no one sells a split boot anymore, at least with those you can
> replace them easily.  You might call these guys to see if they have anything
> though:
> http://www.dormanproducts.com/c-255-cv-joint-boot-kits-solvent-welded-split-
> boot.aspx
> 
> Or look for used OEM boots!
> 
> Stuart
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Craig Cowan
> Sent: Friday, March 22, 2013 8:30 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Cv boots cracking
> 
> Because it doesn't need to be serviced at this interval! I just rebuilt some
> with a friend that were original to the bus and have never been serviced (
> he's the original owner). 140,000 miles and 26 years of use, and the boots
> we took off were fine!
> So why do mine suck?
> 
> -craig