I sometimes see a set of used regulators pop up on craigslist for about $100.  Normally, they're about 20 years old, and have spent the last 10 years sitting in a closet.  Would you be comfortable using a set like that, if you had it serviced at a dive-shop?

Wouldn't be prudent without prior inspection by someone qualified to do so. Life and death. Don't bargain hunt in that way.

If I could get an Atomic for $100 I'd probably get a speeding ticket driving over there.

Have it serviced. Some friends are usung SP regs from the ‘80s. They don’t just go bad.

It really depends on the reg. Few years back I was at the local dive shop waiting while the employee helped a woman picked up regs her husband had brought in for service. Turned her had bought them off eBay. They were so old that parts were no longer available. The labor costs were about $200. Must have been multiple sets. Anyway, she was really angry she had to shell out $200 for service on regs that couldn’t be used.

Let that be your warning. If you know what you’re looking at with used regs, that’s one thing. But I’ve seen some people think their old stuff from the 70s and 80s are still good.

That's a pretty shitty dive shop if they didn't tell her all of that up front or as they found out. If they've been doing it a while they should have an idea of what's so old it might need a special order on parts or whether it'll be usable. That's like shelling out $200 for a mechanic to tell you they can fix your car.

I believe ScubaPro still makes parts kits for old regs. I wouldn't expect the same from some other makers.

Buy once cry once definitely applies to regulators though.

I heard the shop saying they had let the husband know. I know they always emailed me a receipt when regs were ready to be picked up, but whether or not the husband told the wife or if she was just bitching about the cost, I don’t know.

Fair enough. Maybe not as shitty. Or maybe the husband is an idiot.

The husband is the one who bought the regs off eBay. He IS an idiot.

We talking the bones of Billy the Kid, or something to do with compressed gas?

Compressed gas. You’re in the scuba section, if you didn’t realize.

Yes SP does still make parts for older regs. ScubaPro Mk5 with a 109 secondary os still a goid choice.
I have an Oceanic reg set that will probably outlive me. FX10, Delta 4 and Octo 8. Still breathes easy.

If you are reliant on a local shop, find out what they service first.

There are a few Mfg's that will not support their older lineup (eg Oceanic, Tusa)

Mfg that support older models:
 Aqualung (+US Divers)
 Scubapro
 Sherwood
 Mares (no Dacor support)

Of course there are caveats to this, but overall their support is there.  Service Kits are readily available.  Some parts maybe not so much.

In addition to a regular service, you may need hoses.  This is where it adds up fast lol.  Bubble in a compass.  Fogged out SPG.
I made a killing not too long ago with this stuff lol.
Your shop, I hope, would go over this with you when you drop them off for service.  The set does not need to be disassembled to see where the money is.

Having said that, I would still buy used.  Rarely pay what they ask for.  I bought 2 complete sets of MkII/190 for $120 not too long ago.  Before that an AL Legend set for $60.

ScubaPro or Poseidon only

Yes I’d trust a used regulator….. but….

Make sure before you drop your cash that your dive shop can service it.

Scrapped a couple old regs I got for free from an older couple that was giving up diving because when I took them in, the dive shop told me they couldn’t even get parts for them anymore.

I've bought used regulators from dive stores with a guarantee.