Depends a bit on one's subject matter. Walking around town during the day with the Rolleiflex, I check the meter a few time during the day and it was always the same reading. Deep in the redwoods with LF, it would be difficult without a meter for me -- even though I have been photographing in the same area of redwoods for 30+ years. Large variation of light depending on the cover, and the deepness of the shadows within a short walking distance.