Knowing when to begin blood trailing could be dictated by weather as well. A warm early season evening will make an anxious hunter even more anxious to get in the woods and find their trophy to avoid spoiling meat. A rainstorm about to commence will also dictate your feelings as to when to begin trailing. 

Also, pay attention to timing as it relates to still being able to take home some fresh venison. If you put a bad gut shot on a deer at 7:30pm, the deer may live until 4:00am or longer for example, giving you an opportunity to recover the deer and salvage the meat, if you track and find the deer at first light in the morning.

If you did not see or hear the deer crash, but the hit was great—give it a little time, sneak out of the tree and go recover the arrow (if possible) for more intel. If you didn’t see or hear the deer crash, but you have a great hit with a blood covered arrow, I would still give it at least 30 minutes to an hour before tracking. The deer is probably dead, but you just never know.