Yes, I use a tempering bath as well, at school with their water panel and a stainless sink, and at home with a print tray and a Kodak siphoning washer and manual control of the hot an cold valves. (It is much more of a pain controlling two knobs at home rather than one at school!) It still drops about 3 F however, losing temperature out the top of the Nikkor tank that is not submerged, I suppose. Perhaps it is time to make the switch to plastic tanks instead of my old Nikkors.
I use the Kodak chems and mix a gallon at a time. The developer (cheap) is good for 60 rolls of 135 or 120, or six weeks. It will usually expire before I get to 60, but I don't bother to mix the chemicals unless I can process at least 32. Thus, I tend to hold my film for a while. It goes faster when doing sheet film, as I use 250mL at a time one shot to do ten sheets.
The bleach is good for twice the capacity of the developer, with no time limit. The bleach is half the cost of a whole kit, so this makes it even more economical.
It really saves you the big bucks with sheet film, but you still get a worthwhile savings on roll film...worthwhile if you have the time and are a penny pincher.
I would agree that if you don't shoot much, and only process with normal development when you do, there is no point. The main reason I process my own roll film is that I push my roll film at least one stop probably 75% of the time, and often two. Also, I shoot a lot in these situations, so my lab fees would be out of hand.
This is part of the reason I am moving heavily toward digital for my low-light pix. It's a lot of time and expense for not all that many (and hard to print) keepers with film. I hate to waste the silver, chemistry, and time on pix that somebody is just going to want in a digital file format anyhow. With digital you get to shoot more and have to pay nothing and far less time processing. In low light with small format, I am seeing less and less point in shooting film unless I intend for the final result to be on a wall or in a portfolio or book.
Also, since the punchy Ultra Endura on which I relied for low light printing is now DISCONTINUED, most of the pictures I was getting on film in low light are very hard to print. They were hard even on Ultra, but now it is often impossible to get them the way I want them.
Also, I *honestly* love the high-ISO low-light images from my 10D and 1D. I shoot it just like I shoot film (except about twice as many shots), and process it well, and it looks great for grungy grainy pix. 20D and later don't look the same. Same with 1D Mk. II. Too glazed over.
Dare I say that I actually like these shots better than film in many cases? This is coming from someone who is devoted to using film in all its incarnations, and who has shot tons and tons and tons of film in low light. It's important to judge results, not technical details. I like both. I can't discount digital just because it's digital.
What I am getting at is that you need to examine your own shooting habits in detail before deciding whether or not to process your own.