I've been a teacher for 8 years, I changed careers after two years on an grad programme in industry.
For those saying people knew what they were getting into when they became a teacher - actually no we didn't, or at least we didn't realise how much things would change.
I knew that I wouldn't earn as much as I would if I stayed in accounting, but I did think i would still earn enough to have a reasonably comfortable life without having to worry about money. I was willing to earn slightly less if it meant I would work in a job which I would find genuinely interesting, have more autonomy in my day to day work, feel I was doing something worthwhile rather than helping rich people get richer.
Expect, now, 8 years in, I can't lead a comfortable life in my salary. I am constantly worrying about money, while watching friends in a wide variety of other jobs have far more disposable income than me. I have zero autonomy. to the extent that I have to use centralised resources which I am not allowed change in any way. I don't feel I am making any different in the lives of young people, as the school doesn't seem to care that much about young people, just about how they can use the young people to get an outstanding Ofsted report. I've watched 4 colleagues leave just at Easter, two Computing teachers leaving for positions in industry, one ECT leave for a grad scheme in insurance and 1 to set up their own tuition business.
So I've enrolled in an accountancy qualification which I can do the initial study at home until I get a entry level job in this area. I'm lucky that I speak fluent French and German which I'm hoping will get me an entry level accounting position as there are lots of job adverts like that in my area. Any annoyingly, the salaries being advertised for entry level positions isn't a whole lot off what my current teaching salary is with 8 years experience.
So even if teaching was an amazing job, there's no way I could justify staying in the profession when I look at what my salary could be in 3-5 years time compared to if I stayed in teaching. And at this stage, I don't care about working in a job where the sole purpose is helping rich people get richer, as long as I myself can afford a reasonably decent lifestyle in the future.