I like to take my camera for camping and bushwalking. The conditions are typically dirty, dusty and sometimes muddy and wet. The K-7 weather proofing is perfect, but I try to minimise any change/swap of lenses.
Last month, I went camping for 4 days and we had rain, mud, wind and dust. The weather was miserable. I took my 18-250mm as my main lens and the Nokton 58mm for some low light shooting. I changed twice the lens: that is, not much.
Off course everyone has different usage and needs, and I respect that.
Hope that the comment will help ...