Half of my pictures I take during activities like bush-walking, hiking, tramping or skiing. Some times I try to record the adventure and to tell the story to share it with others. More often I go out for a couple of days and try to capture my vision of nature on film, not creating a real story. The physical conditions on this trips can be extremly hard for the material. This feature is very important for the quality.
Slides have to be tack-sharp.
Weight and size. Important if you carry all you have on yourself. Probably its discomforting to fumble with a camera during a starting blizzard, or on a exposed mountain ridge. I also like working with my camera as a user-friendly versatile tool, when I have plenty of time to take the shot. But the number of keepers per roll are an important issue for me.