How long do you play a game before it gets boring?

[RCTjunkie]

First day: 3-6 hours
Second day: 2-5 hours
Third day: 1.5 - 4 hours
If I still like it, then .25-2 hours per day until:
1p game: Game is complete
Multi: 3 months, then come back after another 3 months.