Well, the game is not in completion yet. There's going to be more stuff added(my prediction). But so far, it took me 1-2 years, somewhere between that.
Have you completed the game and how long did it take you?
So far the current content of the game takes a little more than 1 month of realtime gameplay. My wizards have all taken between 2-3 months each to complete all the worlds.
in theory, it took me almost 4 years to reach current end-game. that's including all the waiting in-between.
when i started playing, the level cap was 50-60. it took me about 6 months to get my first wizard to cap, then i started over with another one, etc. it was only when avalon was released that 3 of them eventually caught up to each other; all 3 are now maxed out, but only one has finished the game.