I've kept OC on hand for 8 years now, and EDC'd it for the last 4. I've trained with it for as long too. I see a lot of LE training online has more to do with getting hit with it and trying to continue to function well enough to protect your sidearm and so on. I'm not a masochist, so I just train hitting paper plate targets. Inert training cans are sold, but after as many years, I just use up old or expiring cans. Every six months is a good interval and it serves as both a test of the equipment (which I do not re-use), and a refresher on how the nozzle works and what to expect from the stream or spray cone. I carry a small stream can with a pocket clip, but work it out whether stream, spray or foam is best for you in the various places you might keep it. For the vehicles and house, I like the big cans.
In 8 years, I've not had to use it. There was once when I needed it and wasn't carrying it. That's when I started EDC. Most probable target for me is dogs that attack because of my own dog, including stray dogs and coyotes. But I also live where I can encounter bears several times a year. Of the many bears I've come across, I've never encountered an aggressive one though. I've always just admired them, but they can aggressively pursue food in your camp. My dog is more than enough to keep them away though. Other dogs, not so much.