How long can you devote to a game in one sitting?

As I’ve gotten older — seriously, so old, ice forms on my north side — I simply have a hard time devoting the same kind of time to a video game as I used to. Back in 2004, I could spend six hours playing World of Warcraft and think nothing of it. Nowadays, after about two hours, I simply don’t have the energy to keep going, I’m forced to get up, go for a walk, do something else for a while to get my batteries to recharge.

I think part of that is the fact that WoW and other MMO’s have a social component to them — I can play a single player game with no need to interact with other people for longer, but even then about three hours is my limit before I have to save and quit and go do something else for a while. I just don’t have the ability to devote my time and focus to a game for the same length I once did, whether it’s because my body or my mind feels fatigued or what have you. Needs like food, sleep, bio breaks — yes, it’s a euphemism for bodily waste elimination, just let me have this — all chip away at my focus and mean that by hour three of a big WoW session I’m practically useless.

I’m curious how long others can devote to a game in one go like this — is it merely a feature of age, or perhaps personal responsibilities? I mean, I’m married now, I have to devote some time to my relationship, and other players have kids to deal with. We all have to work, procure food so we can continue to live, and so on. Is there something inevitable about this, that we invariably have less time we can game in one session?