How long is normal for playing a MMORPG?

Keen, who has a reputation for going through hype and disappointment cycles faster than the rest of us, is writing about hype and disappointment cycles. He says "I’m worried about those who DON’T follow the pattern at this point. They are the weird ones." And to some extent I agree. Anybody who starts a new MMORPG these days with the idea to play it nearly every day for the next 5 to 10 years is either deluding himself, or seriously weird. There might still be some nutters out there who confuse playing in a virtual world with some sort of pseudo-religious experience, but fortunately that isn't the norm any more.

Having said that, I was somewhat disappointed that SWTOR didn't last a bit longer than it did for me. I kind of lost interest just 6 weeks after release. I would have hoped for at least 3 months. If we start measuring how long a MMORPG keeps us interested in weeks instead of months, there is barely any more difference left between a MMORPG and an offline single-player game. And there simply aren't enough big MMORPGs coming out each year to keep playing MMORPGs all the time if you go through each game in less than 2 months.

So what is a "normal" time span for playing a MMORPG for you? What are your expectations how long you will play the upcoming MMORPGs of 2012? And how do those expectations fit with your history of the last few years?