With almost 70 Manga volumes, over 580 Anime episodes, 14 movies, and 2 live dramas - Detective Conan doesn't seem to have lost any steam with both the Manga and Anime still in production. With such a proliferation of episodes, you would think that Detective Conan would get stale and lose its popularity. While, character designs and storyline start to get a little similar, overall the show has continued to do well being ranked in the top 10 in popularity contests and winning excellence awards.
The thing that I enjoy most about Detective Conan is that the cases that Conan has to solve are all self contained in one or two episodes. You don't even have to watch the cases in order since there are only minor references to previous cases. While the gimmicks and tricks that are used to both commit and solve the crimes can get stale, the twists are fun and interesting enough to keep you guessing. Detective Conan also does quite well in the longer movie format, presenting more complicated cases not found in the 23 minute episodes. Classic 90s Anime at its height, great storytelling, fun characters, and solid whodunit cases make Detective Conan an Anime you can't miss.