This is something that
@victorzamora and I got into some pretty heated arguments for literally years about.
- Cells-you don't actually need cells annually. You need cells when you need cells. Budget for them annually, but some may go 4 months, some may go 24 months. Don't replace cells until they need to be replaced, same as rebuilding regulators every year. Rebuild them when they need it.
- Sorb/gas-need a full scrubber when you need a full scrubber. If you are doing 2 hour dives, that 2-3 dives depending on scrubber size. A recent study was done that says partially used sorb can just sit around for months and be just as good, if not better, than it was when you finished the first dive. Budget a pound an hour and you're saying 20 technical dives, but you'll use the CCR for most everything at least for a while. 20 tech dives@2hrs=40hrs so round up and say 100hrs/yr. Gas use is about a liter/minute of O2 and Dil which rounds up to say 300cf of each.
- $400 in sorb
- $150-300cf of O2 at rounded up Amigos pricing *$0.46/cf*
- $200-300cf of 18/45 at rounded up Amigos pricing *50/50 of $0.17 EAN32 and $0.96 helium*
- The o-rings and flapper valves don't need to be replaced annually, and if you're smart you'll find the sizes and buy them in bulk. Maybe $50/year if you over buy them, and then you'll have to service the two extra first stages every couple of years, so budget $50/year in reg rebuilds.
- $300 in miscellaneous fills for deco/bailout bottles or the random open circuit dives, etc.
- I won't include any open circuit stuff because you will need it for both situations, so this list is "in addition to my normal OC stuff".
So roughly speaking, you'll be shelling out $1400 in consumables for the rebreather. You'll pro Ish, but that's for 100 total hours of diving. Right now you're saying 20 dives/year which is probably around 40 hours, and it's costing you around $2500/year in gas bills, not including any non-technical diving that you're doing. It will save you roughly a grand a year given your current diving habits *with a LOT of assumptions so don't quote me on any of it. Your gas pricing may be higher than Amigos pricing by more than what I rounded them up to which is the only one that would make it super wonky. Everything else is pretty conservative.
Saving $1k/year in dive costs then has to outweigh the buy-in price. You're in for $10k in a brand new CCR with Mod1 training. Probably $12k if you go the GUE route with the GUE-JJ *I have no idea what that actual cost is*. Add another $1500 for redoing normoxic trimix since you can't use OC normoxic as a pre-req for hypoxic *which is retarded, but whatever*, then another $1500 for hypoxic.
If that investment pays off, then you can justify the rebreather on gas savings. Saving $1k a year though doesn't do much for you. If you increase the trimix dives because it isn't so cost prohibitive and go from 40hrs to 100hrs, then you're now saving almost $5k/year in helium and it's a no-brainer. If you want to justify it based on other factors like extra warmth, silence, no tick-tock from the SPG, cool factor, etc etc. then do that. It won't cost you more/year than diving open circuit trimix, but it's a long ROI at 20dives/year
