Gabor, you really give your bodies a workout ! My M4 is a backup to my MP, but I use the M4 as an everyday carry camera with a summaron 35mm lens. I got my 19 year old daughter a cute "Mini Diana" camera with a flash. It shoots either 48 to 72 frames on a standard 135 Film. Hence the beauty of photography, it really doesn't matter what age you start, stop, or re-start, its an expression, a joy and as some would debate an art form.
Hey I love my FM also. It's bigger and been through hell. I've done some self-repairs even. I hope you can sort out the M7 problems....If get another, I'd say get an M4. They are sturdy and reliable. I love mine. A quik pic taken at coffee last week....