The rate and volume I shoot and process film at is dictated by a fun little interplay of time, budgets, and whether or not I find things that I feel are worth the effort of getting on film.
2-4 rolls of 120 for a developing session is the "General target", as I develop black and white film by hand at home, and that is what readily fits nicely in the tanks I have while making good use of developer. I threw the dice on the double-load scheme, and it has been working well so far, barring a few moments of being an idiot.
Currently I have a single reel and a two reel tank, with a second two reel on the way. I started with just the single reel tank, and rather quickly found it to be annoying when I had a several rolls from a single weekend. So I added the larger tank, and extra reels with the idea that I was very unlikely to shoot more than six rolls of film in a short period of time, but I could have spare dry rolls to reload the larger tank if needed. (Handling and pouring chemistry for 2 120 reels fits nicely with the measuring cups I have on hand. Two reels is a comfortable size to work with, and I feel confident in maintaining consistency with that volume that I don't really have if I start going to longer tanks.)
Reloading the previous tank in the same development session was rather quickly dismissed after just one session, as it was kind of annoying to have to stand there and complete the wash of the first load, hang the film, dry the tank, and then run off to the changing back to reload. And since I was ordering a Mod54 anyway...
So now I have two tanks for two reels, and one tank for a single reel, and can easily run a development session for between one and ten rolls of film. Or one and six rolls of film plus 6 sheets.
I'll normally aim to develop a run of film after I have enough for a single tank, ideally the four rolls, simply because that is the least amount of overall work for the most frames, and fits nicely into part of a Sunday afternoon and then ideally that evening to review, scan, and catalog the negatives for later work.
I like to see the results in a reasonable time, and friends/family will nag if I let too many weeks go by before images are shared. I'm happy to wait a few weeks or even a month or two before running a batch while I 'stock up' on film to process, but I'm not a fan of letting exposed film sit too long,... So it becomes a balance thing.