3" groups at 25 yards is plenty fine to go and get a deer. If you can keep your groups that tight consistently then you are all set for that range and under. Some good things have been mentioned already.........like make sure you can do it with broadheads and not just fieldtips. Also your first shot is all you really get so IMO group shooting is nice BUT I prefer real world practice. I will nock an arrow and just imagine I am shooting at a deer for real........one shot, sometimes I shoot quick, sometimes I hold for a LONG time and sometimes I end up somewhere in between. No matter how I shoot I go pull the arrow and see how I would have done if it was a real deer. I'm also not very fond of practicing with fieldtips for hunting. Since I don't plan on shooting a deer with a fieldtip I don't see the point in shooting them for practice for long periods of time. I shoot them for about a month and then I shoot broadheads the rest of the summer and fall. I have a bunch of friends that shoot fieldtips right up to a couple days before the season and then strap on a broadhead and see how they fly.........that is crazy IMO. Practicing with broadheads not only prepares you for the real thing but also gives you the peace of mind in knowing your rig is in fine hunting condition. I also practice a lot from a ladder stand in my backyard instead of shooting from the ground because I hunt from a stand and not the ground.........I try to keep my practice as real as I can.