I don't recall the last time I left the house to do work without knowing in advance what I'd be doing. In fact, I make it a point to find out in as much detail as I can. Like my grandmother used to say, "What the mind doesn't do, the feet have to."
I don't have any standard set of job site tools. I choose the tools I need to take on a case by case basis. I might help a friend with plumbing, electrical, setting tile, framing, finishing, etc. This weekend was replacing part of a driveway and later on a fire pit build. A coping saw and a sharp set of chisels wouldn't have been much help
Even when I did remodeling for a living, I did a variety of job types. Some tools stayed on the vans all the time, others swapped in and out depending on the type of job. I spent a fair bit of time making sure everyone had the right tools and materials going to the job site. A trip back to the shop or to the store is expensive, especially when you're paying someone to drive around instead of work.
-- Dan Rode
"We are what we repeatedly do. Excellence, then, is not an act, but a habit." - Aristotle