My wife is a teacher here in Miami and her union dues are around $1,000 a year. I work for the school system also; however, not long enough to join the union. The school system has, I believe, at least six unions to cover the various types of employment. Yes, even is you are not part of the union, you do benefit from their efforts.To my knowledge it is not common in Australia for Churches to pay cleaners to clean the Church. Most are volunteers.
And this raises an interesting side topic. I noticed on another Christian forum that it is common for Christian Churches in America to pay professional singers/musicians for their music industry. Is that right? In my experience, there are plenty of willing volunteers to take on the music ministry role in Catholic Churches in Australia. In some parishes it is almost competitive.
Last November, during the general election, a bill was passed that will result in a 20% pay raise for all teachers in our county. It starts in August of this year and was the first pay raise in about 10 years. New teachers are not paid all that well, but teachers who have been around for a while are not paid bad. I believe my wife, who has been around for over 15 years and has a master's degree, is paid a little over $60k. With her 20% raise, that's another $12k. So, $72k a year is not bad for a job where you get the summers off. Oh, if she teaches a "6th period supplement" (six classes a day), that's another 6k.
Keep in mind; however, that the cost of living in Miami is really high.
The teachers here are not allowed to go on strike, so it has never happened. In other places, especially those with really low salaries, I can see why they do it.