Not that it's ideal but many people get into the habit of having a beer or two or a glass of wine of an evening as part of their daily routine.
I believe that regardless of the actual quantity 'necessarily' if someone continues to drink despite the negative consequences of said drinking they could be said to have a drinking problem.
You'd have to judge whether that's the case with your friend. If this pattern has being increasing or becoming more frequent than what was normal for your friend that could also be an indication that something is amiss. Would/do they react negatively if something inteferes with their opportunity to have their few drinks each day? Do they do out of their way to ensure their few drinks - e.g. if after getting home from work they discovered they were out of beers would they just wait till the next time they were at the store or would they have to go and pick some up that evening? Again theses would be indicators of a degree of reliance/dependence.