I'm not a big fan of blazers. I like the way they look, especially on guys, but wearing them during teaching isn't the most practical thing on earth. Most blazers are heavy, hot, the sleeves are too long on me, and most of them require dry cleaning, which I haven't gotten into the habit of doing. Probably never will.
However, I do own two blazers that I wear on occasion:
This one is a brown tweed material. Short-sleeved so I don't get too hot in those little tin-can portables that are either freezing or burning up. It keeps my core body warm, but ventilated as well. I like how it fits on me. Also the fun, puffy cap sleeves. Downside = it doesn't have pockets.
This is a more traditional black blazer that was meant to be part of a suit set. I didn't buy the pants because at the time I already had a pair of black pants. Now those black pants have died, and I'm realized that I don't really like plain black pants of the Dockers style, so I usually wear it with my dark grey pants, or a skirt. It has HUGE pockets, fits my keys, phone, post-it notes, random things I take away from students, a pen, pencil, AND eraser, with still enough room to put my hands in them to keep warm during yard duty. Downside = shoulder pads add heft and weight.
I usually wear these on days when I'm meeting parents, being observed by the principal/my supervisor/someone else important like that. Or for job interviews. If I ever get a job interview.