All great advice.
Even if you see or hear the deer go down, do not hurry to it, give it at least 1/2 hr more if you are not pressed for daylight, or rain isn't an issue.
After the shot, I had a deer lay down within 30 yds of my stand last year, and I thought that was it. It was a morning hunt, good weather conditions. I knew the shot was too low and at a steep angle, but THE DEER WENT DOWN, I SAW IT - I hoped for 1 lung. I sat still for 1/2 hour, and was getting ready to get down when he got up and slowly wandered off. I was sick! I waited another 1/2 hr then snuck out and came back 4 hours later. Coyotes had pushed him out of the area - at a dead run some time after I left. I trailed him over 500 yds to a huge field, where he disappeared. The blood was very sparce after the intitial 30 yds. Turns out, it was a brisket shot, and the deer likely evaded the coyotes and made it ok, but I'll never know for sure.
I'm not an unexperienced bowhunter (20 yrs at it) - but I made a mistake. The deer appeared jumpy, he approached from my entrance point. I waited for a slightly quartering away shot, and PURPOSELY aimed a little low, expecting the deer to react to the sound of the bow by ducking a little. I will never do this again on a deer within 20 yds, as I now know that even a "duck" of 8" would put my arrow in the spine, had I been aiming where I should have been. As you might have surmised, the deer did not react, and I even hit a couple inches lower than my aiming point. I had a classic "bleeding brisket shot" that never hit a vital organ, yet the deer STILL laid down, most likey confused about what happened.
The reason for my story is two fold. Do not trust what you see, assume the worst. Second, even veteran hunters make mistakes on occasion. I think I was one that got "blistered" last year for taking a "bad shot" on this board. IF you do have a bad hit, take your time and do not bump your deer. If you hit a non vital area, you will not likely recover the deer - regardless of how long you let it lay. At least you will know that you did the best you could, and its likely the deer will survive.
