How often do you use/need a 50 amp to 30 amp adapter?

Funny thing, I bought one since we had an allotment to use in the store when we bought our new 5er. That very same night we went to a private campground to test our 5er so we could tell if there was anything that needed repairing before we went 500+ miles home. When we got to the campg ground, the 30 amp didn't work, so I grabbed the 50 to 30 adapter I had just bought. I had never needed one before then, and haven't needed it since. But, we also mainly boondock or drycamp.