In the 1970s and 1980s a Leica M4 rangefinder with a 1970s 35mm Summicron lens was my carry around film camera. It worked extremely well and I was very comfortable wandering the streets using the camera without a light meter. Some say that this was a classic M -- the apex of the minimal analog, hand-crafted design. But it was on the cusp of fading into oblivion in the face of a newer technology of the 35mm SLR from Japan (Nikon F) from the early sixties. The latter was a steady trend which increased even more during the 1970s and 1980s.
I used the M4 extensively for the Bowden Archives and Industrial Modernity project, especially for the black and white photos in the Snapshots and Bowden sections.
I dropped the Leica M4 onto a concrete floor in the Queensland Art Gallery in Brisbane's South Bank in the 1990s. The rangefinder mechanism broke and it could not be repaired in Australia. The camera body was misplaced and then lost for approximately 25 years. The 35mm Summicron lens, which had sat in a cupboard was eventually used on a digital Sony NEX-7 in 2014. I bought the Sony E mount so that I could use the lens.
Then the Leica M4 body was found around 2018. Unfortunately, the rangefinder mechanism still could not be repaired in Australia as there were no second hand rangefinder mechanisms. Over the next couple of years I saved up some money and I sent the body back to Leica Camera in Wetzlar, Germany in 202 to be repaired. They put in a new rangefinder mechanism and refurbished the body. They did an excellent job --- the 1970s camera is like new.
