There is no right or wrong answer here. If it does not dictate or impact your life, I'd say you are fine. But if you start noticing that it does, it would cause me some concern (if it were me personally). But I'd say 20+ drinks per week is more than medical professionals would be comfortable with.
Not to get preaching, but that's a lot of calories to drink too. If you aren't offsetting those, you will likely gain weight pretty quickly. At 4 beers per day and 125 calories per beer, that's 3,500 calories per week in beer consumption alone. That's 1 lb/week of weight gain (again, if you aren't working it off) or 50+ lbs per year. To each his own but some people may not take into account the nutritional aspect of that much beer drinking.
I personally have all but stopped drinking during the week as I found as I get older, even the slightest hangover or foggy head impacts me at work the next day. So I'll limit most of my drinking to the weekend (but drink about every weekend). But again, that's just what I like to do. Everyone is different.