I stuff 4 boxes full of supplies, parts, and tools, plus my regular toolbag. Sometimes I'll bring additional boxes of parts on top of that for specific stuff, and/or an additional box of parts organizers full of LED bulbs.

One of those boxes has a large stack of parts organizers with a lot of commonly used electronics components (resistors, capacitors, diodes, POTs, connector housings and pins, header pins, etc)

Another one of those boxes has all of my soldering tools and supplies.

If I were doing house calls, this would not be enough. I'd need to have a lot more parts on-hand to be efficient. Some guys who actually do house calls have stacks of drawers installed in their vans with parts and tools. With what I carry around, I'd probably have to make 2-3 trips plus one or two parts orders for a house call on a neglected game. I'm not sure if that would be fair to a potential customer, and would end up being a lot of traveling for me.