I had a really long daily chess game once (link).
Started: Nov 23, 2011
Finished: May 7, 2013
Time: 1 move per 7 days
It really depends on how long the game is and how fast you and your opponent play. Some bulldog games take less than a week, while others take several months. The longest so far took 7 months.
Wow! That's even longer than the daily chess games!