[whpalmer4]

I live in semi-rural area, with pretty much a minimum of 15 minutes of driving to get anywhere of interest. I use my various errand contexts (nearly 20 of them, all told) to accumulate both critical and non-critical errands until there is something that needs to get done, NOW, or a big enough collection of "at my convenience" tasks to make it worth taking the better part of an afternoon and mowing down the list. My errands context hierarchy is set up with subcontexts for things like the library, grocery shopping, hardware store, etc. My county library system has online catalog access, and so when I come across mention of some book that interests me, I use the clipping service to drop a URL for the catalog entry in my action list, in the context for the nearest library that has a copy of the book on the shelf. Grocery items go in the grocery store subcontext for the preferred supplier, or the top-level context if any source will do (or getting it today is more important than getting the ideal brand or price). This setup makes it straightforward to make sure I'll get the most out of the time (and gas) invested in a trip "into town" without being particularly onerous to implement. There are some cases that aren't a perfect fit (what do I do if two branches have the book, and are equally convenient? duplicate the item or arbitrarily pick one seem to be the obvious choices, the latter being mine) but for the most part it works well.

In another example of somewhat artificial contexts, I have one for things that need to be scanned. Most things I scan don't have any particular urgency, and it's always a nuisance to clear off enough space around the scanner to scan things that don't fit easily on the scanner bed (books, for example) or to make room to set up the lightbox when scanning negatives. Assigning tasks a context of "scanner" allows me when I do fire up the scanner to be sure that I know what else I should consider doing to amortize the overhead of doing some scanning. It's certainly an artificial context in that any time I want I could walk over and use it, though it would be less artificial if I spent more time working away from home. It also serves as a container of tasks that can be done in the background while doing something else, or in a low-energy, low-concentration period; move the scanner and laptop out into the family room and feed the scanner while watching television.

Similarly, while I do almost always have a telephone handy, most calls that are going to get put in OF are going to be calls to some business or another. I can probably not bother looking at that list of actions at 11:30pm, except when scoping out what I'll need to get done the next day.

So, I find it quite useful to have the context notion, even though I wouldn't attempt to argue that I'm using them in a "by the book" fashion. As BrianOgilvie put it so well, it becomes a planning tool as well as an execution tool.