rjpv:
Thanks.
I'm trying to do the math and figure out what my cost per dive would be if I bought myself some scuba gear (which would then need to be maintained). The nice part is... the more I dive the cheaper it gets
Don't look at it as only a cost factor. Look at the convience of owning your own gear plus the fact that you know you're getting the same "working" gear each time and not having to deal with someone at the dive shop maintaining the rental gear or a customer not reporting a problem with rental gear.
I've rented gear several times only to get in the water and find there was a problem with the gear. Now consider that I drove somewhere like to the beach and this ruined or delayed the dive while we go it fixed. So factor in everything.
A perfect example is owning tanks. By the time you buy tanks and pay the $10 to $15 Visual fee every year and $25 hydro fee every 5 years, it's not much of a break even unless you dive a lot. If you travel (or fly) you typically use tanks at that location, lessening the use of your own tanks. So for that $20/year average maint fee per tank, chances are you could pay the difference in rental tanks and air fills and come out about the same. However, the convience of owning tanks is not having to "rush" to the dive shop on Friday afternoon after work to rent tanks and "rush" to get them back within the rental period. It's just much easier to own tanks and not to have to deal with it. It just costs more for many of us. Especially when you own "lots" of tanks. It's still worth it.
To get back to your orginal question, which more centered on gear(regulators, etc), consider that many new regulators include "Free parts for life" warranties. This cuts down on annual service costs.
You really don't have to service the BC like you do the regulators, but it's still important to inspect it. Look for corrosion on any metal parts, dry rot on any hoses, stitching coming undone on any of hte harnesses, etc. or small holes in the bladder. (you can test be bladder by blowing it up all the way and letting it sit for a few hours and see if it goes down any. If it takes "hours" to go down, you might have a "small pinhole" type leak and not a big deal. just inspect for the leak and it's easy to patch. If it goes down in minutes, then you've got a problem. You don't want that hole to tear bigger while you're trying to obtain neutral bouyancy during a dive.
mike