Paulat, a meat thermometer is recommended for use with ground meats, and a temperature of 155 F. I don't eat hamburgers either.
I don't know anybody who bothers with the thermometer when broiling hamburger meat.
Good ground beef (lean, extra lean, as defined by Canada regulations) is available at better stores here, made up on site from the trimmings of the better cuts.
Luckily we don't have to buy the wrapped or packaged meats, but the cost is higher.

Made ossobuco last week; I watched the butcher select and cut the veal shanks. One of our favorites. Lovely bone marrow as well as the tender meat, and the leftover bones are a treat for the dogs.