To me an old cache implies that it has achieved most of the criteria suggested on the geocaching site for hiding a cache, a great view or something nearby of interest, that kind of thing. Though I have to accept that what I deem as a good cache may not appeal to others, just as puzzles don’t appeal to me! I’d be sad to see the Ten Tors Challenge series go as that got me started as I gradually built my confidence in my GPS and ventured further and further on to the moor. Caches often outlive the owner who’s moved on, or got tired of caching, I can recall several cachers from when I first started who have dropped off the website now. I guess nothing is ever meant to last forever.