I like to build for and hour or so after my 7-3 at work. Building after work helps me cope with the insanity. I also like to actually accomplish something on a Saturday or Sunday afternoon.
Some times I do get stuck away for work for extended periods of time (sometime a month at a time), so my building comes to a stop. Models don't travel when on airplanes and I don't think hotel staff would like me spray painting in my room.