Treestands are not at all necessary. I have used treestands before, but I didn't like it and it didn't help my odds. When I decide to sit and watch an area, I either make a natural blind or just sit at the bottom of a tree. It helps some to be concealed by brush, but if you are statue still it really doesn't matter. Deer won't see you if you don't move. Scent control helps, and if possible try to keep the wind in your favor. If you did your scouting and you are in a good spot, it doesn't matter if you're in a tree or on the ground IMO. It's just a matter of personal preference.