Pretty much you're missing out on free parts for life...
You'll still have to pay the service costs to have those parts installed on their service schedule - usually 1 or two years or a certain dive count. It varies by mfr. Typically it's 1 year inspection 2 year full service. Some
require it to maintain your warranty status. It also varies by dive count. Atomic has a 2 year/300 dive requirement - no inspection. Aqualung has a 2 year - 1st year inspection, 2nd service - or 100? dives. Additionally some of the programs are pretty fussy about the interval - late on one and warranty is revoked.
Aqualung offers FPFL - here's the details.
Free Parts for Life Program
Scubapro does if you buy a full set of gear from them:
http://www.scubaboard.com/forums/scubapro/407051-scubapro-parts-life-policy-explained.html
Atomic doesn't have FPFL but they offer no inspection - just 2nd year service -
Atomic Aquatics Regulator Warranty
Those are the only 3 I follow.
If there was a recall, they should notify you also. We also have a forum here for that in the Q&A sub-forum that's usually pretty current.
One other wrinkle to consider is the service interval. The three I posted above all support/require 2nd year servicing. So although you pay more initially - in the long run you may do better.
I own Atomics - my cost for service/parts is $90. Their base model Z2 is $409 everywhere. Compare that to a $400 other brand reg with an
annual service requirement. By the 4th year you're money ahead - even on a $300 other brand reg during the same interval.
There's also a lot of really old junk on eBay and craigslist.
Some real good deals also - you just have to know how to spot them.And hidden things - corrosion in metal 2nd stages, hopefully the reg was rinsed properly before being stored. Many reg internals are brass - salt water damages/corrodes it over longer intervals. Rotted hoses - they aren't cheap at your dealer either. They probably get $40 or more for them.
Some older 2nd stages that were cast in plastic/poly a decade ago are now brittle and cracking - even though they may look perfectly good, you can't repair the 2nd stage housing and will have to buy another one. That can cost more than the "deal" itself. Your local dealer may be able to help if you can borrow the reg and have it looked at. I wouldn't be averse to paying a small fee for that either - their employee's time is worth money.
If you find something used post a link here and someone will likely know about it. And probably give hints on what to check for. Probably a pretty good guess on vintage also - we have some real reg gurus here.
I occasionally see some good stuff on Craigslist also - someone who took up diving recently but isn't continuing, moving, didn't certify etc. The flipside is a I also see decent looking gear offered by relatives of the deceased for way more than it's worth. My personal philosophy is once it leaves the shop we'll start at 50%. That's what the shop will offer if you bring new gear back - they can't take it back and resell it as new.
Our classifieds is also an option - we'll shame anyone who rips off another member endlessly... But some people here have a slightly inflated opinion of the true worth of their gear IMO - although it's often better maintained.
If you find Dacor regs, don't even bother - there's no parts availability any longer years after the company was purchased by Mares prior to bankruptcy.
I see them on eBay all the time - not sure if it's a scam or people are clueless.
hth,