I'm in the "When I have time" group as well, along with "When conditions are suitable."
- When I have the time if a fairly obvious one, typically done at some point on a weekend. It has often been a Sunday afternoon kind of thing when weekend chores were handled Saturday morning, then the afternoon and Sunday morning (Plus whatever times were handy during the week) get to be used for photography if suitable.
The "When conditions are suitable" have also had to account for other people in the house where I've been living. Taking over a bathroom for a solid block of time when others are likely to want to use it is 'kind of a jerk move'. But for me one of the biggest factors has been whether or not the temperature and humidity is playing nice. I'm currently loading reels in a changing bag, and don't have an air conditioned location to do so. This can make it annoyingly hard to down right nearly impossible to do effectively if my hands begin to sweat more than the tiniest amount.
I also much prefer to process film early enough in the day that they can hang and dry completely before I head to bed.
I have a backlog that I really should have processed weeks ago, but I sadly haven't had the block of time free to get them done and have let myself become distracted by other things. Such is life.
A new place here in the next month or two will hopefully make things far easier. I'll be changing up how I store my gear once I get into a new place, and probably putting together some drying cabinets. I'm hoping that it will make things far easier for 'conditions to be suitable', as it will mean less setup and tear down time - Just go to the 'processing station', take the gear out of the purpose built cabinet by the counter, load film, measure chemistry, process film, hang film, wash everything, and then place directly in the equipment drying-storage cabinet.