We have other obligations too, so we understand. Each company has one meeting and one drill each month. You are expected to attend most of these meetings and drills. There are also special work nights to keep the equipment in repair.
As for emergency calls, you come when you can. Our volunteer system works because there are enough of us to cover any given emergency call. Even a minimum of one call a week will help immensely. Some make more workday calls, while many who work in NYC come more on weekends and evenings.