Unless they drop in sight half hour bare minimum, full hour preferable. That is just until you get down out of your tree and look for clues to the hit. Always remember, just because you THINK you hit the deer good, doesn't mean you did. even after a lot of deer and many years, the eyes/mind can trick you. Lots of bright blood right away typically means a short track. little or dark blood with or without bits of anything in it, means you aren't going anywhere for a while. Gut/liver shot can take anywhere from 4-8 hours to expire. error on the 8 hour side and things will be smoother for you. A shot square thru the center of the liver hitting all the good blood vessels will die out quick. Hitting the outer part of the liver is a different story. The deer can live for several hours. Track slow, quietly and deliberate. I have shot deer that ran from 25-500 yds before dieing. Most are in the 50-60 yd range.