Personally, I will use more than one context only for @computer/@work and @phone/@work. Since I'm using RTM, this allows me to keep all my work related things together, my phone things together, and my computer items together. This way, I can go through my action lists several different ways and still see the item needs done. The combinations I use above could be done both at work and home, but still lets me see all my work related actions in one list. Not something I do all the time, but helpful when necessary.