I agree... The use of one camera only, or more than one, is a very interesting subject... It all depends on how many different situations we want to be prepared for...
To me it's related to light: if there's sun, I'll be shooting sunny AND soft scenes, so I tend to use two bodies, one of them set for sun... I really like to have open, clean shadows on sunny scenes, so I stopped developing harsh and soft light scenes for the same amount of time more than a decade ago. I use the R3A and R4M usually, but sometimes I carry two Ts instead, with the 28 3.5 and the 40 1.4... It's amazing how light Ts are: with those two lenses I just don't feel I'm carrying anything at all... And that set is ready for whatever wherever...
If it's an overcast day and my shooting won't be many hours long, I carry just one body sometimes, and some other times two with the same film, to avoid changing lenses...
Cheers,
Juan