The only deer I've ever spined, I put3 arrows in. I followed up w/ 2 in the vitals. He expired quickly after that.

I only had 4 arrows that day (now i carry more) but I kept one to have on the bow as I approached the animal.

I grew up under the ideology that if it was still moving, and still w/in range, you keep shooting. Even w/ a gun, and even if I know the first shot was good. I've had "sure-things" get away, and dont take chances now. Additionally I like the animals to expire as quickly as possible...