A lot more common than many thinking of only modern Islam might expect. The Classical Islamic state ruled over a variety of people and faiths, and for the first centuries of Islamic rule, non-Muslims still remained the majority of people who were living under the new state. This included, of course, Christians (of various confessional identities), Jews, Zoroastrians, and others, and for many of whom, drinking wine in particular was not only common practice, but a societal norm.

We have Islamic legal texts like the so-called "Pact of 'Umar" (here is one such version, although it comes in many forms) that address this issue directly, where the Muslim law code is saying that you should not be selling alcoholic drinks near Muslim sections of town or too close to Muslim markets, although this last part isn't explicit in this particular version. While the text itself might seem black and white, we might question why laws like this needed to be written and promoted more generally. One likely answer is because these things were regularly occurring, and certain Muslim classes of Islamic society wanted to address and curb the issue directly.

In addition to this, the Arabic narrative sources we have from the early period regularly discuss the consumption of wine at court as if it were a non-issue. In some particular cases, the excessive consumption of wine is used to disparage the quality and characteristics of a past ruler who history was not kind to - the Umayyad Caliph al-Walid b. Yazid is one such example of this.

Thus, in short, classical Islamicate society was extremely cosmopolitan, and the consumption of alcoholic beverages like wine was fairly common. This isn't to say that everyone was doing it of course (and many Muslim religious scholars certainly would have taken issue with it), but for lay members, it was definitely occurring.