All of my life, I've shot manual... until just recently.
In the studio, the lighting is "nailed down" (unchanging) and shooting in ANY auto mode makes no sense.
The way I've worked outdoors is very consistent too... at least stable enough to take a reading off a grey card for each situation.
This past month, I found a location that provides open sky for a light source without need for any subtractive techniques to achieve directional lighting. All I have to do is simply wait for the sun to go below the treeline off to the right and behind me. The location affords me just about 20 minutes or so to work, so I go there with a plan and get a LOT done in that amount of time. HOWEVER, as the sun continues to sink, the quality of light remains good, but the amount of light gradually diminishes rather quickly.
It dawned on me that the camera has a pretty sophisticated metering system, so I set the ISO, put the camera on AV and set the aperture. I gotta tell ya, this was a very freeing experience, allowing me to concentrate on directing and talking with my clients rather than tending to the rapidly changing lighting.
I'm still a bit wary of this. I've never wanted the camera doing anything that I didn't "tell" it to do. But when I sat down at the computer, I was very pleased with the results.
Maybe I'll try auto focus next.
-Pete