Paying $50 for service kits for a first and second stage is an insane markup considering what these kits include; a seat that costs very little to make and a few o-rings and maybe some plastic bushings. Unfortunately it seems to be the going price for most regulator brands. I have older SP regs, I buy the seats separately and source o-rings through reasonably priced alternatives like oringsusa.com or mcmaster-carr. I've found that there are lots of grey market sources for SP parts, and there are friendly dealers that will sell parts to trusted customers despite the idiotic restrictions placed on them by SP.
I used to think that the best thing to do for DIY service was to buy hog or dive rite regs where you can buy the parts openly through dealers. But if they're really charging that much for kits, to me it makes more sense to get older 'classics' where there are lots of parts floating around and/or aftermarket alternatives via the trident catalog. A good place to get older SP kits is vintagedoublehose.com.
As an example, consider a MK5 or 10 and a 109 metal case 2nd stage. Performance wise, this is on par with anything new. The MK5/10 does need a brand-specific hard seat, but you get three of them in a kit, (usually you can use two of the three by adjusting IP shims) and trident makes an acceptable aftermarket seat that's in the vdh kits. Other than that, it's just standard o-rings. The 109 uses a flat EDPM seat that's easily available or even easy to make; awap made a batch for less than a penny/seat, and they work great. Then it's just 2 o-rings. It's easy to get rebuild costs down to a few dollars for these regs. For the center balanced 2nds (D series) the poppet is brand specific but I found a lifetime supply of them on ebay for a good price (less than dealer cost for kits for 3 SP stages) and I'll be gone before they are.
That's the way to save money on service. And it's not a compromise in performance, these old regs work extremely well.
