I left teaching 2 years ago, after 9 years of secondary school teaching. By the time I left I was very disillusioned and extremely stressed. I was not in a great school for the last 5 years and it took its toll.
As for hours - I was in school from 8am to about 4pm. 1-2 times a week I would have a meeting, taking me to about 5pm. I also then had 10 parent's evenings a year, lasting till about 7:30pm.
After school, I would come home and work for a couple of hours or so in an evening, doing my planning and prep, and then do some work at weekends also. I would also work in the holidays.
The work load varies throughout the year and depending on what year group/subject you do. For me, I had a subject with a heavy courseowrk load in GCSE and sixth form years - so my work load was heaviest at holiday time. My lower years had less homework, but I did teach about 7 or 8 different classes - marking was about 1 hour per class per week for me. Prep and planning in addition.
Primary school teachers, I think, tend to spend more time doing their work at the school, whereas I could and did bring my marking home with me.
The paperwork can be heavy - report writing for example!
But the paper work was not my problem. I am a naturally organised person, so paperwork I managed fine.
I struggled, in the end, with the constant class management. In the end there was little teaching happening and constant discipline. This was because of the school I was in partially I know - my first school was veyr different - and the school had very little management support. It was also in special measures, meaning a lot of inspections and general stress. I was physically and verbally assaulted, with little support. I was a good teacher (I know this and have evidence to back me up, but I ran out of ideas in the end, when there was no back up for discipline measures) I posted a lot on MN about these times, and it was support from MN tha made me decide to quit and find a different job - I did and I am happier
I also found that teaching wasn't that family friendly - no taking time of to see your own children in school plays, concerts, nativities, sports day, etc. I was lucky as DH was able to help with the nursery drops, as I had to leave before nursery started.
However in the right school, teaching can be wonderful and fulfilling. I do have some happy memories of my early teaching days and the odd one even from the not so good school. Days when for a child it just clicked or when a child achieved something new - great. You can and do make a difference to a child's life and future as a teacher, and that in itselfcan be fantastic.