Like many others have said it is all a matter of effective range.In addition to that I would add that effective range on a non moving target when nothing is at stake is different than effective range on an animal when you are cold,tired or hyped up with excitement or have been holding for two minutes.In addition to that some days most of us are calmer and stronger than other days.I have had some situations where I have been dead calm and others where a deer has had me pinned and I have been afraid to breathe much less move and when the opportunity presented itself(if it did)I had all that tension coming to the surface.
I would say "to thy own self be true" if you know without a doubt you can kill it cleanly than have at it.If youhave any doubtdon't let the arrow go.