and so am I.

Aggie's formula I think is missing one variable: how much extra energy does it take with all of that kit (in Lbs, Kgs, or Stones) to wander off the path every time you see something that's possibly scenic, but decide otherwise. Somewhere in there belongs a term for:

Scenic Possibilities Evaluated
------------------------------------------- * It would be worth it in (format) but not in (larger format)
Number Actually Photographed.