I’ve struggled with contexts over the years as well, but generally I’ve refined mine down to keep things pretty simple, however I also work from home, and have stopped using OmniFocus as my primary shopping list app, so that allows me to keep things simpler than they used to be.
Home – This is mostly things that need to be done at or around the house. Chores are an obvious example, but it can also be weekend projects or other things I’d like to do in my leisure time.
Arriving Home – This is a location based context for receiving alerts when I’m arriving home. Some things stay in here, some move in and out between the “Home” context during my daily/weekly reviews depending on urgency and what my plans for the day/week are.
Errands - This is a location-based context that fires off when I’m leaving home. Usually it’s things to buy, things to remember to do while I’m out, etc. Defer dates help me keep repeating tasks in here for things like “Get a Haircut”
Desk – As I work from home, this is the opposite of my “Home” context. Same place, different “mode” of operation. When I’m working, I want to see only things that pertain to work. I do, however, include both personal work (e.g. “do taxes”) and actual job work in here.
Calls – As I tend to go into a different mental mode when I’m placing calls, I keep a list of calls I need to place in a separate context. There’s usually not much in here, but I like to break it out as I tend to feel like making calls at different times than when I’m concentrating on doing other work.
Waiting For – Tasks that are waiting for some non-time-determinate action, such as hearing a response back from somebody else. Tasks that are simply deferred to a specific date or time do not go in here.
Simmering Pot – Tasks that require more thought or mental energy. Someday/Maybe stuff goes in here, and other tasks that are on hold because I need to flesh them out with more thought. Kind of a “brainstorming” category for new projects and tasks, as well as stalled, non-critical projects/tasks that need more thought.
On Hold – Things that are on hold for some other reason not covered by the above. This is often simply where tasks go to eventually die, but aren’t ready to be officially dropped because there may be some reason to bring them back to life someday.
The key to my workflow, however, is that I rarely work directly or solely from contexts, preferring to mix them with focusing and perspectives (the app is called Omni Focus after all :) ). For example, I group my Personal and Business world into two completely separate project hierarchies, using folders. Even though I dump everything into the “Desk” context, I often focus on the appropriate parent folder so I’m only looking at actual work tasks or personal life management tasks. So during my working hours, I’d focus on my Work folder, and then work within my contexts and perspectives from there (“Home” is usually empty in that case). Similarly, on the weekend, when I’m in “personal” mode, I focus on my “Personal” master folder. In that case, my “Home” context is usually full, and my “Desk” context has a handful of personal finance type tasks sitting there, ready to be dealt with.
While not directly related to contexts, I should also note that I use defer dates a lot – especially for repeating tasks – but I almost never use due dates. I follow the “hard landscape” concept that only the really, mission critical stuff gets a due date – stuff where serious consequences may occur if the date is missed (whether those consequences be lost projects, late fees or simply an excessive cat mess – I used to have an ornery cat that would choose other places in the house to relieve herself when her highness’ litter box wasn’t changed at exactly the right moment. Needless to say, the ex got to keep that one).
I do maintain a “Hotlist” perspective, which is basically all tasks that are flagged or due, subject to the current focus. I then judiciously use flags to bring things onto that list during my weekly review. My “Hotlist” is essentially my “Today” view, but spread across a couple of days… Due dates for stuff that must be done today, and flags for things that I’d like to get to within the next day or two. Flags and defer dates used together also allow me to have stuff pop onto my “Hotlist” later in the week… I review on Monday, and if I know I’m not going to be able to get to something until Wednesday, but want to deal with it by week’s end, I’ll flag it, and defer it until Wednesday).