Don't let people here rationalize drinking for you if you don't want to. I probably average one beer a week (and almost no other alcohol), while a lot of people I know average one a day or more! I enjoy the taste of good beers, and drinking is the social norm a lot of times, but otherwise I could live without it.
Beer (alcohol) is mildly addictive, so it's good not to have too much in my opinion. One way I avoid drinking by realizing that it's addictive. When I get a craving for a beer, I interpret that as addiction and avoid it. Same goes for caffeine, TV, sugary foods, etc. At some point you won't even crave it any more
For the people that asked about how to make beer last that long, the answer is simple: don't drink so much beer! Or if you want a better answer... I set rules for myself about when I can have beer. For example, I know alcohol interferes with my sleep, so I don't have it after around dinner time during the week. I read that alcohol interferes with memory development/learning, so I avoided it during the week in college, for the most part. I've kept that up, so I really only drink on the weekends. Another personal rule is no drinking and driving, as in not even one drink with dinner if I'm going to drive home later. I know this is conservative since I could likely drive after one beer and would probably still be under the legal limit after two or more, but driving is dangerous so it's not worth it to make it any more risky. Biking after drinking is OK since it's unlikely to harm anyone else (legal limits still apply). Another rule is that I avoid buying beer at restaurants/bars because of the cost. I try to have no more than 2 beers at a time. The result is the only time I can drink is some Friday or Saturday evenings, and I'm OK with that. For me these rules are not strict rules but guidelines. I don't have to follow them, but I try to most of the time. The rules work for me, and and that's important because otherwise there's no way I could stick to them.
For anyone out there trying to reduce your drinking, try setting some rules for yourself. Start with something easy. It can even be completely irrational, like limit one beer on odd days except the third Friday of the month. It might make a good conversation starter!
This is probably an unpopular opinion, given that half the posts here are praising beer! But if I've learned anything from this forum it's that sometimes it's better to question the popular opinion.