I've had a couple of stints of non drinking in recent years, ranging from a few one month offs, a three month and even a six month. While the short ones are good for a quick contrast between the benefits of drinking or not, it is the longer ones that allow you to truly clear your head and think about your relationship with alcohol.
During my six month off stint, I wrote a pros/cons list of drinking and found the pros list was completely dwarfed by the cons list. While I don't have the list on hand at the moment to mention the specifics, the cons list covered numerous behavioural, escapism, social, health and cost issues that were quite scary to look at in totality, despite me never having been what I would consider a problem drinker.
The pros list is easy to remember, as there are very few occasions in which I have found alcohol to have an overall positive effect on a situation for me. These are:
1. A drink or two, but no more, with a special meal. This can significantly enhance the eating and social experience.
2. A drink in the hand sipped slowly over the course of a few hours at a social event. As much as I am happy to not drink at all at social functions, non-drinkers will likely attest to my observation that others can get visibly offended if you are not having a drink to the point where it starts to spoil your experience, especially if they know you used to drink a bit at social events previously. A bit of a cop out I know, but I am talking about an overall positive effect on such a situation.
3. A small drink to toast a special event eg. birthday, NYE, major milestone.
I now try to limit my drinking to such situations in my pros list. Occasionally there will be scope creep (eg. on holiday or around Xmas most evening meals could be rationalised as "special" if you let it), but for the most part I now stick to this. I still like to have the odd month off (January just gone was the last) to keep my perspective on drinking.