Comment by vel0city

I have many times in my less than 40 years of life. Often things that had batteries left in then and forgotten about for a few years, and often with the cheap batteries something came with. Often with kids toys, TV remotes and rarely used flashlights. If you're the kind of person that takes batteries out when you put things away or you change the batteries somewhat soon after they die you likely never had any leak.

I have a Canon AE-1 that takes a 4LR44 to operate the light meter. When I got it the battery had deteriorated significantly, causing a lot of damage to the battery area. I had to remake the battery contacts cutting and soldering in new springs and pads as the corrosion had practically completely eaten the old ones. That was probably the most notable leak I've encountered. But the previous owners didn't even know there was a battery in it, so it likely had that battery in there for a decade or more.