Then what about Ben 10, where does that fall? It began in 2005, and that still has relevancy to this day with various sequels and a reboot, not too different from Adventure Time and Regular Show. Ditto with Samurai Jack being in a same boat as Young Justice as a show that got cancelled by CN and revived for another season.But personally imo, I think everything before 2010 can be considered a "classic" now because even to this day, Adventure Time still has relevancy with Fionna & Cake spinoff, a Regular Show spinoff series has been announced and I believe Gumball isn't completely finished yet. Even Teen Titans Go! hasn't finished yet even if its declining in popularity. I might as well go as far and say that Young Justice, a series that got cancelled by CN ended up getting revived for 2 more seasons, one of those being on MAX. 2010-present CN is modern CN and while those series will be classics one day, I don't know if I can call those "classics" right now.