I've gotten into the habit of resetting the camera to a "base" set of settings whenever I've been tinkering with them. In my case, ISO 100, picture style: standard, WB: Cloudy, Program: aperture-priority, Aperture: f/8. Exposure compensation: 0. Shooting style: Single. Then, if I whip out the camera, the settings are in a known state.
When I go into a shooting situation, I usually go in with a plan. I also take meter readings (incident) in the sunlight, shade, and primary area of interest. I make a decision whether the shots will be hand-held or on a tripod. So before starting, I have an idea of the exposure sets that I can have, whether or not I need a tripod, whether filters will be useful, and whether I will need fill light or not. These decisions probably take 1-5 minutes. After this, I'm making specific decisions on individual photos, but usually within the general parameters already worked out. My camera is set up to show the histogram after every shot, and having a quick look at that either confirms that I'm in the right exposure territory, or allows me to make corrections. If the primary exposure variables are several stops from the "average" reading, I'd be shooting in manual more, otherwise I would usually go with aperture-priority.
When changing environments, it would take me 1-2 minutes to "reconfigure my tricorder" to the new settings, to verify them with a test shot and a scan of the historgram.