A side shot through the lungs/heart is quick and provides plenty of blood to track, but a deer shot through the lungs with an expanding bullet won't often go more than 25 yards. Through the heart, they go about 80 yards.
Either way, they bleed out pretty well.
I once tried to shoot a deer that was limping, but didn't want to ruin more meat. It was only about 50 yards through timber, but I kept trying for a neck shot, but it's front leg had been wounded the neck was going up and down so much, I missed 5 shots. After reloading, one shot through the lungs did the job.