The first one was installed 7 years ago and works like the first day I got it, once a year I use a little wd40 in the key cylinder and the locking mechanism. The only thing that is worn is the tiny rubber strap that attaches the cylinder cap cover to the assembly, the cap still fits snuggly I just watch what I do with it. As for the comment of needing 2 people to lock, I honestly do not get it. Yes, you must hold the lock and pin in place and turn the cylinder with the key to lock it. Simply slide the pin in and push/ pull the hitch to bind the pin, if your hitch is light use your knee to push on the hitch leaving your hands free and you're done.

It almost takes two people to apply the lock once the hitch pin is threaded through the hitch, there's so little tolerance. Push too hard and you push the hitch pin out; not enough and the Master Lock won't lock. It's just too awkward for one person to push the lock on one end with one hand, hold the other end of the hitch pin with the other hand, and turn the key with your third hand (ergo, two people needed). If the locking piece isn't pushed all the way on it won't lock, and that last push seems to be about 1mm only. Given that small tolerance I felt uncomfortable trusting that it would hold without breaking or simply coming loose from not being pushed on well enough, falling off, and thus allowing the hitch pin to work its way out of the hitch. I put my old hitch pin and cotter pin back on the hitch. I'd rather lose my trailer to a thief than to lose it while driving down the road.